U.S. patent number 10,418,666 [Application Number 15/783,460] was granted by the patent office on 2019-09-17 for battery.
This patent grant is currently assigned to Pu Chen, POSITEC POWER TOOLS (SUZHOU) CO., LTD.. The grantee listed for this patent is Pu Chen, Positec Power Tools (Suzhou) Co., Ltd.. Invention is credited to Pu Chen, Yang Liu, Jing Yan.
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United States Patent |
10,418,666 |
Liu , et al. |
September 17, 2019 |
Battery
Abstract
A battery comprises a cathode, an anode and an electrolyte. The
cathode comprises a cathode active material which is configured to
reversibly intercalate-deintercalate a plurality of first metal
ions. The electrolyte comprises at least a solvent configured to
dissolve a solute, the solute being ionized to a plurality of
second metal ions that can be reduced to a metallic state during a
charge cycle and be oxidized from the metallic state to the second
metal ions during a discharge cycle and the first metal ions The
battery further comprises an anode modifier which is selected from
at least one of gelatin, agar, cellulose, cellulose ether and
soluble salt thereof, dextrin and cyclodextrin.
Inventors: |
Liu; Yang (Waterloo,
CA), Chen; Pu (Waterloo, CA), Yan; Jing
(Nanjing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Positec Power Tools (Suzhou) Co., Ltd.
Chen; Pu |
Suzhou
Waterloo |
N/A
N/A |
CN
CA |
|
|
Assignee: |
POSITEC POWER TOOLS (SUZHOU) CO.,
LTD. (Suzhou, Jiangsu Province, CN)
Chen; Pu (Waterloo, Ontario, CA)
|
Family
ID: |
55586473 |
Appl.
No.: |
15/783,460 |
Filed: |
October 13, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180040919 A1 |
Feb 8, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14980257 |
Dec 28, 2015 |
9812738 |
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PCT/CN2014/081029 |
Jun 27, 2014 |
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Foreign Application Priority Data
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Jun 28, 2013 [CN] |
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2013 1 0268836 |
Jun 28, 2013 [CN] |
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2013 1 0269723 |
Jul 12, 2013 [CN] |
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2013 1 0293434 |
Jul 12, 2013 [CN] |
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2013 1 0293478 |
Jul 15, 2013 [CN] |
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2013 1 0296251 |
Aug 9, 2013 [CN] |
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2013 1 0346594 |
Dec 20, 2013 [CN] |
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2013 1 0713128 |
Dec 23, 2013 [CN] |
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2013 1 0717178 |
Jan 2, 2014 [CN] |
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2014 1 0001781 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M
4/366 (20130101); H01M 4/667 (20130101); H01M
4/661 (20130101); H01M 10/38 (20130101); H01M
4/623 (20130101); H01M 4/625 (20130101); H01M
4/42 (20130101); H01M 10/36 (20130101); H01M
4/62 (20130101); H01M 4/663 (20130101); H01M
4/505 (20130101); H01M 2004/028 (20130101); H01M
2300/0005 (20130101); H01M 2004/029 (20130101); H01M
2300/0002 (20130101); H01M 2220/20 (20130101); H01M
2004/027 (20130101) |
Current International
Class: |
H01M
10/36 (20100101); H01M 4/42 (20060101); H01M
10/38 (20060101); H01M 4/505 (20100101); H01M
4/62 (20060101); H01M 4/66 (20060101); H01M
4/36 (20060101); H01M 4/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1770515 |
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May 2006 |
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CN |
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101465421 |
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Jun 2009 |
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CN |
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102035007 |
|
Apr 2011 |
|
CN |
|
102110839 |
|
Jun 2011 |
|
CN |
|
101208818 |
|
Nov 2012 |
|
CN |
|
101208818 |
|
Nov 2012 |
|
CN |
|
102856557 |
|
Jan 2013 |
|
CN |
|
103022472 |
|
Apr 2013 |
|
CN |
|
103030171 |
|
Apr 2013 |
|
CN |
|
103107373 |
|
May 2013 |
|
CN |
|
103531769 |
|
Jan 2014 |
|
CN |
|
103682476 |
|
Mar 2014 |
|
CN |
|
102856557 |
|
Oct 2014 |
|
CN |
|
103107373 |
|
Sep 2015 |
|
CN |
|
2717377 |
|
Apr 2014 |
|
EP |
|
2006116496 |
|
Nov 2006 |
|
WO |
|
WO 2006116496 |
|
Nov 2006 |
|
WO |
|
2012163300 |
|
Dec 2012 |
|
WO |
|
Other References
English language abstract and computer-generated English language
translation for CN102035007 extracted from espacenet.com database
on Jan. 31, 2016; 11 pages. cited by applicant .
English language abstract for CN101208818 extracted from
espacenet.com database on Jan. 31, 2016; 2 pages. cited by
applicant .
English language abstract and computer-generated English language
translation for CN102856557 extracted from espacenet.com database
on Jan. 31, 2016, 15 pages. cited by applicant .
English language abstract and computer-generated English language
translation for CN103107373 extracted from espacenet.com database
on Jan. 31, 2016; 25 pages. cited by applicant .
International Search Report for International Patent Application
No. PCT/CN2014/081029, dated Sep. 2, 2014; 4 pages. cited by
applicant .
English language abstract and computer-generated translation of
CN103682476 extracted from espacenet.com database Mar. 21, 2017, 33
pages. cited by applicant .
English language abstract and computer-generated translation of
CN101465421 extracted from espacenet.com database Mar. 21, 2017, 9
pages. cited by applicant .
English language abstract and computer-generated translation of
CN103030171 extracted from espacenet.com database Mar. 21, 2017, 6
pages. cited by applicant .
English language abstract and computer-generated translation of
CN103022472 extracted from espacenet.com database Mar. 21, 2017, 8
pages. cited by applicant .
English language abstract and computer-generated translation of
CN103531769 extracted from espacenet.com database Mar. 21, 2017, 4
pages. cited by applicant .
English language translation of the International Search Report for
PCT/CN2015/090769, dated Dec. 9, 2015. cited by applicant .
Supplementary European Search Report for European Patent
Application No. EP 15 84 3519, dated Feb. 20, 2018; 8 pages. cited
by applicant .
English language abstract and computer-generated English
translation for CN102110839 extracted from espacenet.com database
on Jan. 31, 2016, 18 pages. cited by applicant .
English language abstract and computer-generated English
translation for CN 102035007 extracted from espacenet.com database
on Jan. 31, 2016, 11 pages. cited by applicant .
English language abstract and computer-generated English
translation for CN 102856557 extracted from espacenet.com database
on Jan. 31, 2016, 15 pages. cited by applicant .
English language and computer-generated English translation for CN
103107373 extracted from espacenet.com database on Jan. 31, 2016,
25 pages. cited by applicant .
International Search Report for Application No. PCT/CN2014/081029
dated Sep. 2, 2014, 4 pages. cited by applicant .
English language abstract only of International Patent Application
Publication No. WO 2012/163300 extracted from www.espacenet.com on
Mar. 5, 2019; see English language equivalent U.S. Pat. No.
9,680,154 B2; 2 pages. cited by applicant .
English language abstract, and machine-assisted English language
translation of Chinese Patent Publication No. CN 102856557 A
extracted from www.espacenet.com on Mar. 5, 2019; 9 pages. cited by
applicant .
English language abstract and computer-generated translation of
CN1770515A extracted from espacenet.com Feb. 27, 2019, 8 pages.
cited by applicant.
|
Primary Examiner: McConnell; Wyatt P
Attorney, Agent or Firm: Howard & Howard Attorneys
PLLC
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser.
No. 14/980,257 filed on Dec. 28, 2015, which is a continuation of
prior PCT Application No. PCT/CN2014/081029, filed Jun. 27, 2014,
which claims priority to Chinese Application No. CN201310268836.5
filed Jun. 28, 2013, Chinese Application No. CN201310269723.7 filed
Jun. 28, 2013, Chinese Application No. CN201310293434.0 filed Jul.
12, 2013, Chinese Application No. CN201310293478.3 filed Jul. 12,
2013, Chinese Application No. CN201310296251.4 filed Jul. 15, 2013,
Chinese Application No. CN201310346594.7 filed Aug. 9, 2013,
Chinese Application No. CN 201310713128.8 filed Dec. 20, 2013,
Chinese Application No. CN201310717178.3 filed Dec. 23, 2013,
Chinese Application No. CN201410001781.6 filed Jan. 2, 2014, the
content of which are incorporated by reference herein.
Claims
The invention claimed is:
1. A battery comprising: a cathode; an anode; and an electrolyte;
wherein the cathode comprises a cathode active material capable of
reversibly intercalating and deintercalating a plurality of first
metal ions; and an anode modifier selected from at least one of a
gelatin, an agar, a cellulose, a cellulose ether and a soluble salt
thereof, a dextrin and a cyclodextrin; wherein the electrolyte
comprises at least a solvent capable of dissolving a solute, the
solute being ionized to a plurality of second metal ions that can
be reduced to a metallic state during a charge cycle and be
oxidized from the metallic state to the plurality of second metal
ions during a discharge cycle and the first plurality of metal
ions; wherein the second metal ions are selected from manganese
ions, iron ions, copper ions, zinc ions, chromium ions, nickel
ions, tin ions or lead ions.
2. The battery according to claim 1, wherein the cyclodextrin is
selected from at least one of .alpha.-cyclodextrin,
.beta.-cyclodextrin and .gamma.-cyclodextrin; the cellulose ether
is selected from carboxymethyl cellulose or hydroxypropyl methyl
cellulose.
3. The battery according to claim 1, wherein the average molecular
weight of the anode modifier is 2,000 to 2,000,000.
4. The battery according to claim 1, wherein the anode modifier is
contained in a coating layer on the surface of the anode.
5. The battery according to claim 4, wherein the coating layer
further includes the second metal ions.
6. The battery according to claim 4, wherein the thickness of the
coating layer is 5-40 .mu.m.
7. The battery according to claim 1, wherein the weight percentage
range of the anode modifier dissolved in the electrolyte is
0.01-2%.
8. The battery according to claim 1, wherein the cathode material
further comprises conductive agent graphite, wherein the particle
size of the conductive agent graphite is less than 50 .mu.m and the
crystallinity of the conductive agent graphite is no less than
90%.
9. The battery according to claim 1, wherein the anions of the
electrolyte include alkyl sulfonate ions, and wherein the alkyl
sulfonate ions are methyl sulfonate ions.
10. The battery according to claim 9, wherein the concentration of
the alkyl sulfonate ions in the electrolyte is 0.5-12 mol/L.
11. The battery according to claim 9, wherein the anions of the
electrolyte further comprise at least one of sulfate ions, chloride
ions, acetate ions and nitrate ions.
12. The battery according to claim 1, wherein the first metal ions
are selected from Li and Na ions.
13. The battery according to claim 1, wherein the cathode comprises
a combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises the cathode active material; the
combined current collector has two opposite surfaces and the
cathode plate is formed on the two opposite surfaces; the battery
comprises two anodes which are sharing the cathode; the anode is
selected from metal, alloy or carbon-based material.
14. The battery according to claim 1, wherein the cathode comprises
a combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises the cathode active material; the
combined current collector has two opposite surfaces and the
cathode plate is formed on at least one surface of the combined
current collector that faces to the anode; the battery comprises
two cathodes which are sharing the anode; the anode is selected
from metal, alloy or carbon-based material.
15. The battery according to claim 1, wherein the cathode comprises
a combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises the cathode active material; the
combined current collector has two opposite surfaces and the
cathode plate is formed on at least one surface of the combined
current collector that faces to the anode; the anode is selected
from metal, alloy or carbon-based material; the battery comprises n
pair of cathodes and anode, wherein n.gtoreq.2; the cathodes and
anodes are arranged alternately, two adjacent cathodes share the
anode which is located between the two adjacent cathodes and two
adjacent anodes share the cathode which is located between the two
adjacent anodes.
16. The battery according to claim 1, wherein the cathode comprises
a combined current collector and a cathode plate which is formed on
one surface of the combined current collector, the combined current
collector comprises a cathode current collector and a conductive
film which is coated on the cathode current collector, the cathode
plate comprises the cathode active material; the battery comprises
at least one bipolar electrode which are located between the
cathode and the anode, the bipolar electrode comprises a bipolar
current collector and the cathode plate, the bipolar current
collector has two opposite surfaces which are defined as a first
surface and a second surface, the cathode plate is formed on the
first surface; the second metal ions that can be reduced to a
metallic state and deposited on the second surface of the bipolar
current collector during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle;
the anode is selected from metal, alloy or carbon-based material;
the electrolyte is located between the cathode and the anode.
17. A battery pack comprising a number of batteries according to
claim 1.
18. An uninterruptible power supply comprising a number of
batteries according to claim 1.
19. A vehicle comprising a number of batteries according to claim 1
being configured as power supply of driven engine.
Description
FIELD OF THE INVENTION
The present invention relates to a battery.
BACKGROUND OF THE INVENTION
Lead-acid batteries, which exist over hundred years and have a
mature technology, have accumulated dominant market share in car
starting batteries, electric bicycles, UPS and other energy storage
areas. Although the cycle life and the energy density are
relatively low, lead-acid batteries characterize high cost
effectiveness. Thus, in recent years lead-acid batteries cannot be
replaced by nickel-metal hydride batteries, lithium ion batteries
and sodium sulfur batteries in energy storage area.
A new ion exchange battery comprises a cathode, an anode and en
electrolyte, the working principle could be summarized as follows:
during the charging process, the first metal ions deintercalate
from the cathode, while simultaneously, the second metal ions in
the electrolyte are reduced and deposited onto the surface of the
anode. Theoretical energy density of the ion exchange battery is
160 Wh/Kg, and the actual energy density is expected to reach
50.about.80 Wh/Kg. Therefore this type of battery could be a
promising alternative of lead-acid batteries in next generation
storage batteries.
However, the electrolytes used in the ion exchange battery are
acetate, hydrochloride, and sulfate. Acetate could be easily
oxidized due to its poor stability, which results in great
self-discharge; Cathode current collector could be corroded in
hydrochloride solution; and the corrosion of anode in sulfate
cannot be ignored.
SUMMARY OF THE INVENTION
The present invention aims to provide an electrolyte for a battery
which has a god chemical stability and suppress the corrosion of
the battery.
According to one aspect the invention provides an electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the anions of
the electrolyte include alkyl sulfonate ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions,
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the concentration of the first metal ions is 1-7 mol/L;
the concentration of the second metal ions is 1-4 mol/L.
Preferably the first metal ions are selected from Li ions; the
second metal ions are selected from zinc ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the electrolyte further comprises an electrolyte
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
More preferably the molar ratio of the sulfate ions and the alkyl
sulfonate ions is 1:21-27:7.
Preferably the pH range of the electrolyte is 3-7.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a cathode material, the cathode material comprises a
cathode active material which is capable of reversibly
intercalating-deintercalating a first metal ions; the anode
comprises a substrate for charge and discharge of the anode; the
electrolyte is provided as above in the invention.
Preferably the anode further comprises an anode additive which is a
bismuth compound
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof; dextrin and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 5.about.40
.mu.m.
Preferably the anode modifier is in the electrolyte of which the
weight percentage range in the electrolyte is 0.01-2%.
Preferably the cathode material further comprises conductive agent
graphite, wherein the particle size of the conductive agent
graphite is less than 50 .mu.m and the crystallinity of the
conductive agent graphite is no less than 90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, the cathode comprises a
combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises a cathode active material which is
capable of reversibly intercalating-deintercalating a first metal
ions; the anode is selected from metal, alloy or carbon-based
material; wherein the electrolyte is as described above.
According to one aspect the invention provides a battery comprising
a cathode, two anodes and an electrolyte, the cathode comprises a
combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises a cathode active material which is
capable of reversibly intercalating-deintercalating a first metal
ions; the combined current collector has two opposite surfaces and
the cathode plate is formed on the two opposite surfaces; two anode
share the cathode; the anode is selected from metal, alloy or
carbon-based material; wherein the electrolyte is as described
above.
According to one aspect the invention provides a battery comprising
two cathodes, an anode and an electrolyte, the cathode comprises a
combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises a cathode active material which is
capable of reversibly intercalating-deintercalating a first metal
ions; the combined current collector has two opposite surfaces and
the cathode plate is formed on at least one surface of the combined
current collector that faces to the anode; two cathodes share the
anode; the anode is selected from metal, alloy or carbon-based
material; wherein the electrolyte is as described above.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, the cathode comprises a
combined current collector and a cathode plate, the combined
current collector comprises a cathode current collector and a
conductive film which is coated on the cathode current collector,
the cathode plate comprises a cathode active material which is
capable of reversibly intercalating-deintercalating a first metal
ions; the combined current collector has two opposite surfaces and
the cathode plate is formed on at least one surface of the combined
current collector that faces to the anode; the anode is selected
from metal, alloy or carbon-based material; the battery comprises n
pair of cathodes and anode, wherein n.gtoreq.2; the cathodes and
anodes are arranged alternately, two adjacent cathodes share the
anode which is located between the two adjacent cathodes and two
adjacent anodes share the cathode which is located between the two
adjacent anodes; wherein the electrolyte is as described above.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, the cathode comprises a combined current collector and
a cathode plate which is formed on one surface of the combined
current collector, the combined current collector comprises a
cathode current collector and a conductive film which is coated on
the cathode current collector, the cathode plate comprises a
cathode active material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; the second metal ions that can be
reduced to a metallic state and deposited on the second surface of
the bipolar current collector during a charge cycle and be oxidized
from the metallic state to the second metal ions during a discharge
cycle; the anode is selected from metal, alloy or carbon-based
material; the electrolyte is located between the cathode and the
anode; wherein the electrolyte is as described above.
Preferably the anode and/or the electrolyte further comprise an
additive which is selected from bismuth trioxide and/or bismuth
nitrate.
Preferably a seal part is formed and arranged at the outer
circumference part of a part of the bipolar current collector.
Preferably the material of the bipolar current collector is
selected from a conductive plastic, stainless steel or passivated
stainless steel.
Preferably the material of the conductive plastic is a conductive
polymer.
Preferably the material of the conductive plastic comprises a
polymer and a conductive agent.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the cathode plate further comprises a carrier which is
electrochemically inert, the cathode active material is formed on
the carrier.
Preferably the carrier has a porous structure and is electrical
insulation.
Preferably the pore size range of the carrier is 50-200 meshes.
Preferably the carrier can conduct electron.
Preferably the material of the carrier is selected from at least
one of polyethylene terephthalate, polybutylene terephthalate,
polyethylene, polypropylene, polyamide, polyurethane and
polyacrylonitrile.
Preferably the carrier is a non-woven fabric.
Preferably the thickness range of the carrier is less than 1
mm.
Preferably the carrier has two opposite surfaces and the cathode
active material is formed on both surfaces of the carrier.
Preferably the cathode active material is formed on the carrier by
means of slurry method.
Preferably the conductive film is a thermoplastic polymer.
Preferably the conductive film is bonded to the cathode current
collector by means of hot pressing, vacuum pumping or spraying.
Preferably the cathode plate is bonded to the combined current
collector by means of hot pressing or bonding.
Preferably the cathode active material has a spinel structure,
layered structure or an olivine structure.
Preferably the cathode current collector is selected from at least
one of glassy carbon, graphite foil, graphite sheet, carbon cloth,
carbon felt, carbon fibers, or Al, Fe, Cu, Pb, Ti, Mo, Co, Ag or
passivated metal thereof or stainless steel, carbon steel, Al
alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh
alloy or passivated alloy thereof.
Preferably the battery further comprises a separator which is
retaining the electrolyte.
Compared with prior art, the electrolyte is not easy to be
oxidized, chemical stable and could effectively improve the
solubility of the first metal ions and the second metal ions,
inhibit the generation of gas, reduce the battery corrosion and
self discharge, and cannot be frozen at -20.quadrature. and has
good low temperature performance.
The present invention aims to provide a battery which could reduce
gas production when being used.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a cathode material, the cathode material comprises a
cathode active material which is capable of reversibly
intercalating-deintercalating a first metal ions; the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; and the anode
and/or the electrolyte further comprise an additive which is a
bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the anions of the electrolyte include alkyl sulfonate
ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
Preferably the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof, dextrin and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 5.about.40
.mu.m.
Preferably the weight percentage range of the anode modifier in the
electrolyte is 0.01-2%.
Preferably the battery further includes a separator which is
located between the cathode and the anode.
Preferably the first metal ions are selected from Li and Na
ions.
Preferably the cathode active material is selected from at least
one of LiMn.sub.2O.sub.4, LiFePO.sub.4 or LiCoO.sub.2.
Preferably the second metal ions are selected from manganese ions,
iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the pH range of the electrolyte is 3-7.
Preferably the cathode material further comprises conductive agent
graphite, wherein the particle size of the conductive agent
graphite is less than 50 .mu.m and the crystallinity of the
conductive agent graphite is no less than 90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the anode is selected from metal, alloy or
carbon-based material; and the anode and/or the electrolyte further
comprise an additive which is a bismuth compound.
According to one aspect the invention provides a battery comprising
a cathode, two anodes and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on the two opposite
surfaces; two anode share the cathode; the anode is selected from
metal, alloy or carbon-based material; and the anode and/or the
electrolyte further comprise an additive which is a bismuth
compound.
According to one aspect the invention provides a battery comprising
two cathodes, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; two
cathodes share the anode; the anode is selected from metal, alloy
or carbon-based material; and the anode and/or the electrolyte
further comprise an additive which is a bismuth compound.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; the anode
is selected from metal, alloy or carbon-based material; the battery
comprises n pair of cathodes and anode, wherein n.gtoreq.2; the
cathodes and anodes are arranged alternately, two adjacent cathodes
share the anode which is located between the two adjacent cathodes
and two adjacent anodes share the cathode which is located between
the two adjacent anodes; and the anode and/or the electrolyte
further comprise an additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, wherein the electrolyte comprises at least a solvent
capable of dissolving solute, the solute being ionized to a second
metal ions and a first metal ions that can deintercalate from the
cathode active material during the charge cycle and intercalate
into the cathode active material during the discharge cycle; the
cathode comprises a combined current collector and a cathode plate
which is formed on one surface of the combined current collector,
the combined current collector comprises a cathode current
collector and a conductive film which is coated on the cathode
current collector, the cathode plate comprises a cathode active
material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; the second metal ions that can be
reduced to a metallic state and deposited on the second surface of
the bipolar current collector during a charge cycle and be oxidized
from the metallic state to the second metal ions during a discharge
cycle; the anode is selected from metal, alloy or carbon-based
material; the electrolyte is located between the cathode and the
anode; and the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably a seal part is formed and arranged at the outer
circumference part of a part of the bipolar current collector.
Preferably the material of the bipolar current collector is
selected from a conductive plastic, stainless steel or passivated
stainless steel.
Preferably the material of the conductive plastic is a conductive
polymer.
Preferably the material of the conductive plastic comprises a
polymer and a conductive agent.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the cathode plate further comprises a carrier which is
electrochemically inert, the cathode active material is formed on
the carrier.
Preferably the carrier has a porous structure and is electrical
insulation.
Preferably the pore size range of the carrier is 50-200 meshes.
Preferably the carrier can conduct electron.
Preferably the material of the carrier is selected from at least
one of polyethylene terephthalate, polybutylene terephthalate,
polyethylene, polypropylene, polyamide, polyurethane and
polyacrylonitrile.
Preferably the carrier is a non-woven fabric.
Preferably the thickness range of the carrier is less than 1
mm.
Preferably the carrier has two opposite surfaces and the cathode
active material is formed on both surfaces of the carrier.
Preferably the cathode active material is formed on the carrier by
means of slurry method.
Preferably the conductive film is a thermoplastic polymer.
Preferably the conductive film is bonded to the cathode current
collector by means of hot pressing, vacuum pumping or spraying.
Preferably the cathode plate is bonded to the combined current
collector by means of hot pressing or bonding.
Preferably the cathode active material has a spinel structure,
layered structure or an olivine structure.
Preferably the cathode current collector is selected from at least
one of glassy carbon, graphite foil, graphite sheet, carbon cloth,
carbon felt, carbon fibers, or Al, Fe, Cu, Pb, Ti, Mo, Co, Ag or
passivated metal thereof or stainless steel, carbon steel, Al
alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh
alloy or passivated alloy thereof.
Preferably the battery further comprises a separator which is
retaining the electrolyte.
Compared with prior art, the anode and/or the electrolyte further
comprises a bismuth compound which can effectively inhibit the
generation of gas, avoid the battery swelling, enhance the safety
performance of the battery and suppress degradation of the battery
performance.
The present invention aims to provide a battery which has a good
safety performance.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a cathode active material which is capable of reversibly
intercalating and deintercalating a first metal ions; the
electrolyte comprises at least a solvent capable of dissolving
solute, the solute being ionized to a second metal ions that can be
reduced to a metallic state during a charge cycle and be oxidized
from the metallic state to the second metal ions during a discharge
cycle and the first metal ions; the battery further comprises an
anode modifier which is selected from at least one of gelatin,
agar, cellulose, cellulose ether and soluble salt thereof, dextrin
and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier 2,000
to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 5.about.40
.mu.m.
Preferably the weight percentage range of the anode modifier in the
electrolyte is 0.01-2%.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the anions of the electrolyte include alkyl sulfonate
ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
Preferably the battery further includes a separator which is
located between the cathode and the anode.
Preferably the first metal ions are selected from Li and Na
ions.
Preferably the cathode active material is selected from at least
one of LiMn.sub.2O.sub.4, LiFePO.sub.4 or LiCoO.sub.2.
Preferably the second metal ions are selected from manganese ions,
iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the cathode material further comprises conductive agent
graphite, wherein the particle size of the conductive agent
graphite is less than 50 .mu.m and the crystallinity of the
conductive agent graphite is no less than 90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the anode is selected from metal, alloy or
carbon-based material; the battery further comprises an anode
modifier which is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
According to one aspect the invention provides a battery comprising
a cathode, two anodes and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on the two opposite
surfaces; two anode share the cathode; the anode is selected from
metal, alloy or carbon-based material; the battery further
comprises an anode modifier which is selected from at least one of
gelatin, agar, cellulose, cellulose ether and soluble salt thereof,
dextrin and cyclodextrin.
According to one aspect the invention provides a battery comprising
two cathodes, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; two
cathodes share the anode; the anode is selected from metal, alloy
or carbon-based material; the battery further comprises an anode
modifier which is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; the anode
is selected from metal, alloy or carbon-based material; the battery
comprises n pair of cathodes and anode, wherein n.gtoreq.2; the
cathodes and anodes are arranged alternately, two adjacent cathodes
share the anode which is located between the two adjacent cathodes
and two adjacent anodes share the cathode which is located between
the two adjacent anodes; the battery further comprises an anode
modifier which is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, wherein the electrolyte comprises at least a solvent
capable of dissolving solute, the solute being ionized to a second
metal ions and a first metal ions that can deintercalate from the
cathode active material during the charge cycle and intercalate
into the cathode active material during the discharge cycle; the
cathode comprises a combined current collector and a cathode plate
which is formed on one surface of the combined current collector,
the combined current collector comprises a cathode current
collector and a conductive film which is coated on the cathode
current collector, the cathode plate comprises a cathode active
material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; the second metal ions that can be
reduced to a metallic state and deposited on the second surface of
the bipolar current collector during a charge cycle and be oxidized
from the metallic state to the second metal ions during a discharge
cycle; the anode is selected from metal, alloy or carbon-based
material; the electrolyte is located between the cathode and the
anode; the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof, dextrin and cyclodextrin.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, the cathode comprises a combined current collector and
a cathode plate which is formed on one surface of the combined
current collector, the combined current collector comprises a
cathode current collector and a conductive film which is coated on
the cathode current collector, the cathode plate comprises a
cathode active material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; wherein the electrolyte comprises
at least a solvent capable of dissolving solute, the solute being
ionized to a second metal ions that can be reduced to a metallic
state and deposited on the anode during a charge cycle and be
oxidized from the metallic state to the second metal ions during a
discharge cycle and a first metal ions that can deintercalate from
the cathode active material during the charge cycle and intercalate
into the cathode active material during the discharge cycle; the
second metal ions that can be reduced to a metallic state and
deposited on the second surface of the bipolar current collector
during a charge cycle; the anode is selected from metal, alloy or
carbon-based material; the electrolyte is located between the
cathode and the anode; the battery further comprises an anode
modifier which is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably a seal part is formed and arranged at the outer
circumference part of a part of the bipolar current collector.
Preferably the material of the bipolar current collector is
selected from a conductive plastic, stainless steel or passivated
stainless steel.
Preferably the material of the conductive plastic is a conductive
polymer.
Preferably the material of the conductive plastic comprises a
polymer and a conductive agent.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the cathode plate further comprises a carrier which is
electrochemically inert, the cathode active material is formed on
the carrier.
Preferably the carrier has a porous structure and is electrical
insulation.
Preferably the pore size range of the carrier is 50-200 meshes.
Preferably the carrier can conduct electron.
Preferably the material of the carrier is selected from at least
one of polyethylene terephthalate, polybutylene terephthalate,
polyethylene, polypropylene, polyamide, polyurethane and
polyacrylonitrile.
Preferably the carrier is a non-woven fabric.
Preferably the thickness range of the carrier is less than 1
mm.
Preferably the carrier has two opposite surfaces and the cathode
active material is formed on both surfaces of the carrier.
Preferably the cathode active material is formed on the carrier by
means of slurry method.
Preferably the conductive film is a thermoplastic polymer.
Preferably the conductive film is bonded to the cathode current
collector by means of hot pressing, vacuum pumping or spraying.
Preferably the cathode plate is bonded to the combined current
collector by means of hot pressing or bonding.
Preferably the cathode active material has a spinel structure,
layered structure or an olivine structure.
Preferably the cathode current collector is selected from at least
one of glassy carbon, graphite foil, graphite sheet, carbon cloth,
carbon felt, carbon fibers, or Al, Fe, Cu, Pb, Ti, Mo, Co, Ag or
passivated metal thereof or stainless steel, carbon steel, Al
alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh
alloy or passivated alloy thereof.
Preferably the battery further comprises a separator which is
retaining the electrolyte.
Compared with prior art, the battery further comprises an anode
modifier which can effectively inhibit the generation of dendrite
and gas, avoid the side reaction between the electrolyte and the
anode, improve the safety performance and cycleability of the
battery.
The present invention aims to provide a cathode material for a
battery which has a good stability and corrosion resistance.
According to one aspect the invention provides cathode material for
a battery comprising a cathode active material which is capable of
reversibly intercalating-deintercalating a first metal ions and a
conductive agent graphite; wherein the particle size of the
conductive agent graphite is less than 50 .mu.m and the
crystallinity of the conductive agent graphite is no less than
90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises the cathode material provided by the invention.
Preferably the electrolyte comprises at least a solvent capable of
dissolving solute, the solute being ionized to a second metal ions
that can be reduced to a metallic state during a charge cycle and
be oxidized from the metallic state to the second metal ions during
a discharge cycle and the first metal ions that can deintercalate
from the cathode active material during the charge cycle and
intercalate into the cathode active material during the discharge
cycle.
Preferably the first metal ions are selected from Li, Na, Mg or Zn
ions.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof, dextrin and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 5.about.40
.mu.m.
Preferably the weight percentage range of the anode modifier in the
electrolyte is 0.01-2%.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the anions of the electrolyte include alkyl sulfonate
ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
Preferably the battery further includes a separator which is
located between the cathode and the anode.
Preferably the cathode active material is selected from at least
one of LiMn.sub.2O.sub.4, LiFePO.sub.4 or LiCoO.sub.2.
Preferably the second metal ions are selected from manganese ions,
iron ions; copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the cathode comprises a combined current collector and a
cathode plate, the combined current collector comprises a cathode
current collector and a conductive film which is coated on the
cathode current collector, the cathode plate comprises the cathode
material; the anode is selected from metal, alloy or carbon-based
material.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises the cathode material which
is provided in the invention; the anode is selected from metal,
alloy or carbon-based material.
According to one aspect the invention provides a battery comprising
a cathode, two anodes and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises the cathode material which
is provided in the invention; the combined current collector has
two opposite surfaces and the cathode plate is formed on the two
opposite surfaces; two anodes share the cathode; the anode is
selected from metal, alloy or carbon-based material.
According to one aspect the invention provides a battery comprising
two cathodes, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode material which is
provided in the invention; the combined current collector has two
opposite surfaces and the cathode plate is formed on at least one
surface of the combined current collector that faces to the anode;
two cathodes share the anode; the anode is selected from metal,
alloy or carbon-based material.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the electrolyte
comprises at least a solvent capable of dissolving solute, the
solute being ionized to a second metal ions that can be reduced to
a metallic state during a charge cycle and be oxidized from the
metallic state to the second metal ions during a discharge cycle
and the first metal ions that can deintercalate from the cathode
active material during the charge cycle and intercalate into the
cathode active material during the discharge cycle; the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode material which is
provided in the invention; the combined current collector has two
opposite surfaces and the cathode plate is formed on at least one
surface of the combined current collector that faces to the anode;
the anode is selected from metal, alloy or carbon-based material;
the battery comprises n pair of cathodes and anode, wherein
n.gtoreq.2; the cathodes and anodes are arranged alternately, two
adjacent cathodes share the anode which is located between the two
adjacent cathodes and two adjacent anodes share the cathode which
is located between the two adjacent anodes.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, wherein the electrolyte comprises at least a solvent
capable of dissolving solute, the solute being ionized to a second
metal ions that can be reduced to a metallic state and deposited on
the anode during a charge cycle and be oxidized from the metallic
state to the second metal ions during a discharge cycle and a first
metal ions that can deintercalate from the cathode active material
during the charge cycle and intercalate into the cathode active
material during the discharge cycle; the second metal ions that can
be reduced to a metallic state and deposited on the second surface
of the bipolar current collector during a charge cycle; the cathode
comprises a combined current collector and a cathode plate which is
formed on one surface of the combined current collector, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode material which is
provided in the invention; the bipolar electrode which is located
between the cathode and the anode comprises a bipolar current
collector and the cathode plate, the bipolar current collector has
two opposite surfaces which are defined as a first surface and a
second surface, the cathode plate is formed on the first surface;
the anode is selected from metal, alloy or carbon-based material;
the electrolyte is located between the cathode and the anode.
Preferably a seal part is formed and arranged at the outer
circumference part of a part of the bipolar current collector.
Preferably the material of the bipolar current collector is
selected from a conductive plastic, stainless steel or passivated
stainless steel.
Preferably the material of the conductive plastic is a conductive
polymer.
Preferably the material of the conductive plastic comprises a
polymer and a conductive agent.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the cathode plate further comprises a carrier which is
electrochemically inert, the cathode active material is formed on
the carrier.
Preferably the carrier has a porous structure and is electrical
insulation.
Preferably the pore size range of the carrier is 50-200 meshes.
Preferably the carrier can conduct electron.
Preferably the material of the carrier is selected from at least
one of polyethylene terephthalate, polybutylene terephthalate,
polyethylene, polypropylene, polyamide, polyurethane and
polyacrylonitrile.
Preferably the carrier is a non-woven fabric.
Preferably the thickness range of the carrier is less than 1
mm.
Preferably the carrier has two opposite surfaces and the cathode
active material is formed on both surfaces of the carrier.
Preferably the cathode active material is formed on the carrier by
means of slurry method.
Preferably the conductive film is a thermoplastic polymer.
Preferably the conductive film is bonded to the cathode current
collector by means of hot pressing, vacuum pumping or spraying.
Preferably the cathode plate is bonded to the combined current
collector by means of hot pressing or bonding.
Preferably the cathode active material has a spinel structure,
layered structure or an olivine structure.
Preferably the cathode current collector is selected from at least
one of glassy carbon, graphite foil, graphite sheet, carbon cloth,
carbon felt, carbon fibers, or Al, Fe, Cu, Pb, Ti, Mo, Co, Ag or
passivated metal thereof or stainless steel, carbon steel, Al
alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh
alloy or passivated alloy thereof.
Preferably the battery further comprises a separator which is
retaining the electrolyte.
Compared with prior art, the conductive agent of the cathode
material has the suitable particle size, which can be well balanced
with the electric conductivity and stability, thus avoid the
corrosion of the conductive agent graphite, reduce the gas
production of battery, enhance the safety performance of the
battery, and also effectively suppress the battery performance
degradation.
The present invention aims to provide a battery which has a good
cycleability and high energy.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the anode is selected from metal, alloy or
carbon-based material; the electrolyte comprises at least a solvent
capable of dissolving solute, the solute at least being ionized to
a second metal ions that can be reduced to a metallic state as an
anode active material which is deposited on the anode during a
charge cycle and be oxidized from the metallic state to the second
metal ions during a discharge cycle.
According to one aspect the invention provides a battery comprising
a cathode, two anodes and an electrolyte, wherein the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating and deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on the two opposite
surfaces; two anode share the cathode; the anode is selected from
metal, alloy or carbon-based material; the electrolyte comprises at
least a solvent capable of dissolving solute, the solute at least
being ionized to a second metal ions that can be reduced to a
metallic state as an anode active material which is deposited on
the anode during a charge cycle and be oxidized from the metallic
state to the second metal ions during a discharge cycle.
According to one aspect the invention provides a battery comprising
two cathodes, an anode and an electrolyte, wherein the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; two
cathodes share the anode; the anode is selected from metal, alloy
or carbon-based material; the electrolyte comprises at least a
solvent capable of dissolving solute, the solute at least being
ionized to a second metal ions that can be reduced to a metallic
state as an anode active material which is deposited on the anode
during a charge cycle and be oxidized from the metallic state to
the second metal ions during a discharge cycle.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions: the combined current collector has two opposite
surfaces and the cathode plate is formed on at least one surface of
the combined current collector that faces to the anode; the anode
is selected from metal, alloy or carbon-based material; the battery
comprises n pair of cathodes and anode, wherein n.gtoreq.2; the
cathodes and anodes are arranged alternately, two adjacent cathodes
share the anode which is located between the two adjacent cathodes
and two adjacent anodes share the cathode which is located between
the two adjacent anodes; the electrolyte comprises at least a
solvent capable of dissolving solute, the solute being ionized to
at least a second metal ions that can be reduced to a metallic
state as an anode active material which is deposited on the anode
during a charge cycle and be oxidized from the metallic state to
the second metal ions during a discharge cycle.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, wherein the cathode comprises a combined current
collector and a cathode plate which is formed on one surface of the
combined current collector, the combined current collector
comprises a cathode current collector and a conductive film which
is coated on the cathode current collector, the cathode plate
comprises a cathode active material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; the electrolyte comprises at least
a solvent capable of dissolving solute, the solute being ionized to
at least a second metal ions that can be reduced to a metallic
state and deposited on the second surface of the bipolar current
collector as an anode active material during a charge cycle and the
anode active material be oxidized from the metallic state to the
second metal ions during a discharge cycle; the anode is selected
from metal, alloy or carbon-based material; the electrolyte is
located between the cathode and the anode.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
According to one aspect the invention provides a battery comprising
a cathode, at least one bipolar electrode, an anode and an
electrolyte, wherein the cathode comprises a combined current
collector and a cathode plate which is formed on one surface of the
combined current collector, the combined current collector
comprises a cathode current collector and a conductive film which
is coated on the cathode current collector, the cathode plate
comprises a cathode active material which is capable of reversibly
intercalating-deintercalating the first metal ions; the bipolar
electrode which is located between the cathode and the anode
comprises a bipolar current collector and the cathode plate, the
bipolar current collector has two opposite surfaces which are
defined as a first surface and a second surface, the cathode plate
is formed on the first surface; the electrolyte comprises at least
a solvent capable of dissolving solute, the solute being ionized to
a second metal ions that can be reduced to a metallic state and
deposited on the anode during a charge cycle and be oxidized from
the metallic state to the second metal ions during a discharge
cycle and a first metal ions that can deintercalate from the
cathode active material during the charge cycle and intercalate
into the cathode active material during the discharge cycle; the
second metal ions that can be reduced to a metallic state and
deposited on the second surface of the bipolar current collector as
a second metal during a charge cycle and the second metal be
oxidized from the metallic state to the second metal ions during a
discharge cycle; the anode is selected from metal, alloy or
carbon-based material; the electrolyte is located between the
cathode and the anode; and the battery further comprises an anode
modifier which is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
According to one aspect the invention provides a battery comprising
a cathode, an anode and an electrolyte, wherein the cathode
comprises a combined current collector and a cathode plate, the
combined current collector comprises a cathode current collector
and a conductive film which is coated on the cathode current
collector, the cathode plate comprises a cathode active material
which is capable of reversibly intercalating-deintercalating a
first metal ions; the anode is selected from metal, alloy or
carbon-based material; the electrolyte comprises at least a solvent
capable of dissolving solute, the solute being ionized to at least
a second metal ions that can be reduced to a metallic state as an
anode active material which is deposited in the anode during a
charge cycle and the anode active material be oxidized from the
metallic state to the second metal ions during a discharge
cycle.
Preferably the number of the cathode is one and the number of the
anode is two; the cathode comprises a combined current collector
and a cathode plate, the combined current collector has two
opposite surfaces and the cathode plate is formed on the two
opposite surfaces; two anode share the cathode.
Preferably the number of the cathode is two and the number of the
anode is one; the combined current collector has two opposite
surfaces which are defined as a first surface and a second surface;
the first surface faces to the anode; the cathode plate is formed
on at least the first surface; two cathodes share the anode.
Preferably the cathode comprises a combined current collector and a
cathode plate, the combined current collector has two opposite
surfaces, the cathode plate is formed on at least one surface that
faces to the anode; the anode is selected from metal, alloy or
carbon-based material; the battery comprises n pair of cathodes and
anode, wherein n.gtoreq.2; the cathodes and anodes are arranged
alternately, two adjacent cathodes share the anode which is located
between the two adjacent cathodes and two adjacent anodes share the
cathode which is located between the two adjacent anodes.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the battery further comprises at least one bipolar
electrode, the cathode comprises a combined current collector and a
cathode plate which is formed on one surface of the combined
current collector, the bipolar electrode which is located between
the cathode and the anode comprises a bipolar current collector and
the cathode plate, the bipolar current collector has two opposite
surfaces which are defined as a first surface and a second surface,
the cathode plate is formed on the first surface; the second metal
ions that can be reduced to a metallic state and deposited on the
second surface of the bipolar current collector as a second metal
during a charge cycle and the second metal be oxidized from the
metallic state to the second metal ions during a discharge cycle;
the anode is selected from metal, alloy or carbon-based material;
the electrolyte is located between the cathode and the anode.
Preferably the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof, dextrin and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 5.about.40
.mu.m.
Preferably the weight percentage range of the anode modifier in the
electrolyte is 0.01-2%.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the anions of the electrolyte include alkyl sulfonate
ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
Preferably the battery further includes a separator which is
located between the cathode and the anode.
Preferably the first metal ions are selected from Li and Na
ions.
Preferably the cathode active material is selected from at least
one of LiMn.sub.2O.sub.4, LiFePO.sub.4 or LiCoO.sub.2.
Preferably the second metal ions are selected from manganese ions,
iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the pH range of the electrolyte is 3-7.
Preferably the cathode material further comprises conductive agent
graphite, wherein the particle size of the conductive agent
graphite is less than 50 .mu.m and the crystallinity of the
conductive agent graphite is no less than 90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
Preferably a seal part is formed and arranged at the outer
circumference part of a part of the bipolar current collector.
Preferably the material of the bipolar current collector is
selected from a conductive plastic, stainless steel or passivated
stainless steel.
Preferably the material of the conductive plastic is a conductive
polymer.
Preferably the material of the conductive plastic comprises a
polymer and a conductive agent.
Preferably the anode is selected from at least one metal of Zn, Ni,
Cu, Ag, Pb, Mn, Sn, Fe, Al or passivated metal thereof or an alloy
thereof, or at least one of graphite foil, graphite sheet, carbon
cloth, carbon felt, carbon fibers, or tinned copper or brass.
Preferably the cathode plate further comprises a carrier which is
electrochemically inert, the cathode active material is formed on
the carrier.
Preferably the carrier has a porous structure and is electrical
insulation.
Preferably the pore size range of the carrier is 50-200 meshes.
Preferably the carrier can conduct electron.
Preferably the material of the carrier is selected from at least
one of polyethylene terephthalate, polybutylene terephthalate,
polyethylene, polypropylene, polyamide, polyurethane and
polyacrylonitrile.
Preferably the carrier is a non-woven fabric.
Preferably the thickness range of the carrier is less than 1
mm.
Preferably the carrier has two opposite surfaces and the cathode
active material is formed on both surfaces of the carrier.
Preferably the cathode active material is formed on the carrier by
means of slurry method.
Preferably the conductive film is a thermoplastic polymer.
Preferably the conductive film is bonded to the cathode current
collector by means of hot pressing, vacuum pumping or spraying.
Preferably the cathode plate is bonded to the combined current
collector by means of hot pressing or bonding.
Preferably the cathode active material has a spinel structure,
layered structure or an olivine structure.
Preferably the cathode current collector is selected from at least
one of glassy carbon, graphite foil, graphite sheet, carbon cloth,
carbon felt, carbon fibers, or Al, Fe, Cu, Pb, Ti, Mo, Co, Ag or
passivated metal thereof or stainless steel, carbon steel, Al
alloy, Ni alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh
alloy or passivated alloy thereof.
Preferably the battery further comprises a separator which is
retaining the electrolyte.
Preferably the anode and/or the electrolyte further comprise an
additive which is a bismuth compound.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the weight percentage range of the bismuth compound in
the electrolyte is 0.01-5%.
Preferably the weight percentage range of the bismuth compound in
the anode is 0.1-10%.
Preferably the anions of the electrolyte include alkyl sulfonate
ions.
Preferably the alkyl sulfonate ions are methyl sulfonate ions.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
Preferably the anions of the electrolyte further comprise at least
one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
Preferably the battery further comprises an anode modifier which is
selected from at least one of gelatin, agar, cellulose, cellulose
ether and soluble salt thereof, dextrin and cyclodextrin.
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and .gamma.-cyclodextrin;
the cellulose ether is selected from carboxymethyl cellulose or
hydroxypropyl methyl cellulose.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Preferably the anode modifier is contained in a coating layer on
the surface of the anode.
Preferably the coating layer further includes the second metal
ions.
Preferably the thickness of the coating layer is 518 40 .mu.m.
Preferably the weight percentage range of the anode modifier in the
electrolyte is 0.01-2%.
Preferably the battery further includes a separator which is
located between the cathode and the anode.
Preferably the first metal ions are selected from Li and Na
ions.
Preferably the cathode active material is selected from at least
one of LiMn.sub.2O.sub.4, LiFePO.sub.4 or LiCoO.sub.2.
Preferably the second metal ions are selected from manganese ions,
iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions.
Preferably the solvent is an aqueous solution or alcohol
solution.
Preferably the pH range of the electrolyte is 3-7.
Preferably the cathode material further comprises conductive agent
graphite, wherein the particle size of the conductive agent
graphite is less than 50 .mu.m and the crystallinity of the
conductive agent graphite is no less than 90%.
Preferably the graphite comprises a first graphite and a second
graphite, the particle size of the first graphite is 15-50 .mu.m
and the particle size of the second graphite is 5 to 15 .mu.m.
Preferably the weight percentage range of the first graphite and
the second graphite in the graphite are 30-50% and 40-60%
respectively.
Preferably the particle size d10 of graphite is 6 .mu.m.
Preferably the particle size of graphite is greater than 0.5
.mu.m.
Preferably the weight percentage range of the conductive agent
graphite in the cathode material is 6-15%.
Preferably the cathode comprises a combined current collector and a
cathode plate, the combined current collector comprises a cathode
current collector and a conductive film which is coated on the
cathode current collector, the cathode plate comprises a cathode
material; the anode is selected from metal, alloy or carbon-based
material;
The electrode plate is easy processing and sorting and has a
uniform thickness and performance consistency. The battery using
this electrode plate has a low price, good cycle performance and
high energy. Therefore, the battery of the invention could be
widely used in large-scale energy storage, power grids and other
fields.
The invention also provides a battery pack which comprises a
plurality of batteries provided by the present invention.
The invention also provides an uninterrupted power supply which
comprises the battery provided by the present invention.
The invention also provides a vehicle, which comprises the battery
provided by the invention as an engine driving power source.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention will become more apparent in the
following detailed description in which reference is made to the
appended drawing wherein:
FIG. 1 schematically shows battery structure in cross section in a
first embodiment;
FIG. 2 schematically shows bipolar electrode structure in the first
embodiment;
FIG. 3 schematically shows battery unit in the first
embodiment;
FIG. 4 schematically shows battery charging principle in the first
embodiment;
FIG. 5 schematically shows battery structure in cross section in a
second embodiment;
FIG. 6 schematically shows battery unit in the second
embodiment;
FIG. 7 schematically shows battery structure in cross section in a
third embodiment;
FIG. 8 schematically shows battery structure in cross section in a
fourth embodiment;
FIG. 9 schematically shows battery structure in cross section in a
fifth embodiment;
FIG. 10 schematically shows battery unit in the fifth
embodiment;
FIG. 11 schematically shows battery structure in cross section in a
sixth embodiment;
FIG. 12 schematically shows battery structure in cross section in a
seventh embodiment, wherein the number of the cathode and anode is
two;
FIG. 13 schematically shows battery structure in cross section in
the seventh embodiment, wherein the number of the cathode and anode
is greater than two;
FIG. 14 schematically shows electrode plate structure, wherein an
active material layer is formed on a first and second surface of
the carrier;
FIG. 15 schematically shows electrode structure in cross
section;
FIG. 16 schematically shows electrode structure in cross section,
wherein the electrode current collector has a conductive film;
FIG. 17 comparatively shows gas production amount in example a1 and
ac1;
FIG. 18 comparatively shows gas production amount in example c1 and
cc1;
FIG. 19 is an internal resistance-charge and discharge time curve
of batteries in example r1 and rc1;
FIG. 20 is a voltage-discharge capacity curve of batteries in
example r3 and rc2;
FIG. 21 is a cycles-discharge capacity curve of batteries in
example r4;
FIG. 22 is a cycles-discharge capacity curve of batteries in
example r5.
Wherein:
TABLE-US-00001 1. electrode plate 2. carrier 4. active material
layer 6, 10. electode 8. current collector 12. conductive film 20.
battery 22, 40. cathode 23. cathode plate 24. bipolar electrode 26.
anode 28. electrolyte 30. cathode current collector 32. bipoalr
current collector 321. first surface 322. second surface 34.
seperator 36. seal part 38, 46. battery unit 42. cathode 44. anode
50. cathode active material 100, 200, 300. battery 400, 500, 600.
battery 700. battery
DETAILED DESCRIPTION OF THE INVENTION
The following description of the preferred embodiment(s) is merely
exemplary in nature and is in no way intended to limit the
invention, its application or uses.
An electrolyte for a battery comprises at least one solvent capable
of dissolving solute, the solute being ionized to at least a second
metal ions that can be reduced and deposited on an anode to form an
anode active material, and the anode active material can be
oxidized to the second metal ions dissolved in the electrolyte.
Preferably the electrolyte also comprises a solute that can be
ionized to at least intercalation-deintercalation ions that can
deintercalate from a cathode during the charge cycle and
intercalate into the cathode during the discharge cycle.
Specifically, both the second metal ions and
intercalation-deintercalation ions are metal ions. The
intercalation-deintercalation ion is referred to as a first metal
ion. Thus the electrolyte comprises the first metal ions and the
second metal ions. During the charge cycle the second metal ions
can be reduced to a second metal which is deposited on the anode,
and during discharge cycle the second metal can be reversibly
oxidized to the second metal ions.
The solvent is to dissolve the solute and eventually the
electrolyte has cations and anions which can move freely.
Preferably the solvent is an aqueous solution and/or an alcohol
solution, the alcohol includes but is not limited to methanol or
ethanol.
The first metal ions in the electrolyte can deintercalate from the
cathode active material during the charge cycle and intercalate
into the cathode active material during the discharge cycle.
Preferably the first metal ions are selected from lithium ions and
sodium ions; and more preferably the first metal ions are lithium
ions.
The second metal ions in the electrolyte can be reduced to a
metallic state as a second metal and deposited on the anode during
a charge cycle and the second metal can be oxidized from the
metallic state to the second metal ions during a discharge
cycle
Preferably the second metal ions are selected from manganese ions,
iron ions, copper ions, zinc ions, chromium ions, nickel ions, tin
ions or lead ions; and more preferably the second metal ions are
zinc ions.
In a preferred embodiment, the first metal ions are selected from
lithium ions, while the second metal ions are selected from zinc
ions, i.e. the cations of the electrolyte include lithium ions and
zinc ions.
Preferably the anions of the electrolyte include alkyl sulfonate
ions. The alkyl sulfonate ions include but are not limited to
aliphatic sulfonate ions. The aliphatic sulfonate ions include but
are not limited to that with a functional group or a substituent on
the aliphatic group. Preferably the formula of the alkyl sulfonate
ions is as follows: R--SO.sub.3-or Y--R'--SO.sub.3-
Y refers to a substituent group, such as --F, --OH, etc.
R may be a branched or unbranched aliphatic group; which may be an
aliphatic group with 1 to 12 carbon atoms, preferably with 1 to 6
carbon atoms, more preferably R is a methyl group, an ethyl group
and n-propyl.
R' may be a branched or unbranched aliphatic group; and R' may be
an aliphatic group with 2 to 12 carbon atoms, preferably with 2 to
6 carbon atoms, more preferably R' is a unbranched aliphatic group
with 2 to 6 carbon atoms; more preferably the sulfonic acid group
and a substituent group are not attached to the same carbon
atom.
More preferably the alkyl sulfonate ions are methyl sulfonate ions,
i.e., R is methyl.
The anions of Electrolyte are methyl sulfonate ion, which can
further enhance the solubility of the first metal ions and the
second metal ions, and of which the cost is relative lower than the
other alkyl sulfonate.
Preferably the electrolyte contains only one kind of anions which
are the alkyl sulfonate ions, thus the electrolyte has an excellent
low-temperature properties and higher concentration of the first
metal ions and the second metal ions.
More preferably the solutes of the electrolyte are alkyl sulfonate
zinc and alkyl sulfonate lithium.
Of course, the electrolyte may also comprise the other anions
besides alkyl sulfonate ions. The other anions can be any kind that
does not affect the electrochemical reaction in cathode and anode,
and the dissolution of alkyl sulfonate in solvent. For example, the
other anions may be sulfate ions, chloride ions, nitrate ions,
acetate ions, formate ions, phosphate ions and mixtures
thereof.
In a preferred embodiment, the electrolyte further comprises at
least one of sulfate ions, chloride ions, acetate ions and nitrate
ions.
More preferably the molar ratio of sulfate ions and alkyl sulfonate
ions is 1:21 to 27:7.
More preferably the electrolyte comprises alkyl sulfonate ions and
sulfate ions.
The concentration of ions in the electrolyte can be regulated
through the type of solute and solvent and the application fields
of battery.
Preferably the concentration of the first metal ions in the
electrolyte is 1.about.7 mol/L.
Preferably the concentration of the second metal ions in the
electrolyte is 1.about.4 mol/L.
Preferably the concentration of the alkyl sulfonate ions in the
electrolyte is 0.5.about.12 mol/L.
In order to make battery's performance more excellent, the
electrolyte preferably further comprises an electrolyte
additive.
In a preferred embodiment, the electrolyte additive is a bismuth
compound.
The methods of adding a bismuth compound to the electrolyte can be
varied, depending on the electrolyte or separator. The methods
include but are not limited to adding a bismuth compound into the
electrolyte directly, or adding a suspension with a bismuth
compound to the separator. More preferably a bismuth compound is
added directly to the electrolyte, and then the electrolyte is
dropped to the separator.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
The amount of the bismuth compound in the electrolyte is preferably
as follows:
When the electrolyte additive is a bismuth trioxide, the bismuth
trioxide is 0.01 to 5% by weight of the total electrolyte.
When the electrolyte additive is a bismuth nitrate, the bismuth
nitrate is 0.01 to 5% by weight of the total electrolyte.
Of course, the electrolyte additive can be a mixture of bismuth
trioxide and bismuth nitrate.
Preferably the electrolyte further comprises an anode modifier; the
anode modifier is selected from at least one of gelatin, agar,
cellulose, cellulose ether and soluble salt thereof, dextrin and
cyclodextrin.
The anode modifier aims to improve the deposition of the second
metal on the anode and suppress dendrite generation of the second
metal, thereby improve the safety performance of battery.
Preferably the average molecular weight of the anode modifier is
2,000 to 2,000,000.
Among them, gelatin is generally comprises a partially hydrolyzed
collagen which is contained in animal bones or skins.
Preferably the average molecular weight of gelatin is 2,000 to
150,000.
The agar refers to a colloidal substance made by certain seaweed;
the main component of the agar is polygalactose.
The cellulose refers to a linear macromolecule polysaccharide which
is formed by more than 300 glucose units being connected through
.beta.-1,4 glycosidic bonds. The molecular formula of cellulose is
(C.sub.5H.sub.10O.sub.5).sub.n. The cellulose includes, but is not
limited to .alpha.-cellulose, .beta.-cellulose, and
.gamma.-cellulose.
Preferably, the average molecular weight of cellulose is 500,000 to
2,000,000.
Cellulose ether and soluble salt thereof refer to a derivative of
cellulose in which the hydrogen of hydroxyl is substituted by
alkyl. such as methyl cellulose and its soluble salt, hydroxyethyl
cellulose and its soluble salt, carboxymethylcellulose and its
soluble salt, ethylcellulose and its soluble salt, benzyl cellulose
and its soluble salt, hydroxyethyl cellulose and its soluble salt,
hydroxypropylmethyl cellulose and its soluble salt, cyanoethyl
cellulose and its soluble salt, benzyl cyanoethyl cellulose and its
soluble salt, carboxymethyl hydroxyethyl cellulose and its soluble
salts, phenyl cellulose and its soluble salt.
Preferably the cellulose ether is selected from carboxymethyl
cellulose (CMC) or hydroxypropylmethyl cellulose (HPMC).
More preferably carboxymethyl cellulose has a degree of
substitution in the range of 0.8 to 1.1.
Dextrin is a sugar obtained by partially hydrolyzing starch under
acid, heat or amylase, of which the molecular mass is much less
than starch. Dextrin includes but is not limited to white dextrin,
yellow dextrin or British gum.
Cyclodextrin is a general term for a series of cyclic
oligosaccharide which are generated from amylase under the action
of cyclodextrin glycosyltransferase, which usually contains 6 to 12
D-glucopyranose units. For example, cyclodextrin is
.alpha.-cyclodextrin (six glucose units), .beta.-cyclodextrin (7
glucose units) and .gamma.-cyclodextrin (eight glucose units).
Preferably the cyclodextrin is selected from at least one of
.alpha.-cyclodextrin, .beta.-cyclodextrin and
.gamma.-cyclodextrin.
Specifically the anode modifier is dispersed in the electrolyte of
a battery.
When an anode modifier is dispersed in the electrolyte, the formed
dispersion could be a liquid solution or a colloidal solution based
on the kind of the anode modifier.
Preferably the anode modifier is 0.01 to 2% by weight of the total
electrolyte.
The way to disperse an anode modifier in the electrolyte could be
adding an anode modifier directly to the electrolyte, or adding an
anode modifier and the solute to a solvent to get an
electrolyte.
In order to enhance a particular performance of battery (such as
low temperature performance, high temperature performance, rate
discharge performance, etc.), or make battery suitable for
different applications, the electrolyte of the present invention
may also contains other additives, such as low temperature
additives, high temperature additives, overcharge additives,
etc.
In order to optimize the performance of a battery, the pH range of
the electrolyte is preferably 3-7, which ensure the concentration
of the second metal ions in the electrolyte and avoid co-embedment
of protons. Then a battery with the electrolyte in the present
invention has a high capacity and rate discharge performance.
The Electrolyte of the present invention containing alkyl sulfonate
ions has the following advantages: Firstly, alkyl sulfonate ions
can improve the solubility of the first metal ions (e.g., lithium
ion) and the second metal ions (e.g. zinc ions) in the electrolyte,
the increasing of ions concentration in the electrolyte can
effectively improve high rate charge and discharge performance of
battery; secondly, alkyl sulfonate ions can suppress gas
generation; Thirdly, alkyl sulfonate ions can also effectively
reduce the self-discharge rate of battery; the reasons therein may
be alkyl sulfonate ions can improve the oxygen evolution
overpotential of the electrolyte and reduce the oxidation-reduction
potential of cathode active material; fourthly, compared to other
anionic salt, the electrolyte with alkyl sulfonate ions cannot be
frozen at -20.degree. C., which make a battery have a better low
temperature performance.
The method of preparing the electrolyte depends on actual
situation. The preferable method is as follows.
Method I: Alkyl Sulfonate is Directly Dissolved in a Solvent.
Appropriate amount of methyl sulfonic acid lithium and methyl
sulfonic acid zinc are weighed and dissolved in water according to
the desired ions concentration. The resulting solution is stirred
and an electrolyte is obtained. In the electrolyte, the anions are
methyl sulfonate ions, and the cations are zinc ions and lithium
ions.
Method II: Metal Reacts with Alkyl Sulfonic Acid
Appropriate amount of metal zinc is weighed and dissolved in methyl
sulfonic acid with certain concentration, stirred until completely
dissolved; then lithium hydroxide is added and stirred until
completely dissolved, at last an electrolyte is obtained. Methyl
sulfonic acid completely reacts with metal zinc and lithium
hydroxide; metal zinc is reduced to zinc ions in the electrolyte,
lithium hydroxide reacts with methyl sulfonic acid to form methyl
sulfonic acid lithium.
Method III: Metal Oxide Reacts with Alkyl Sulfonic Acid
Appropriate amount of zinc oxide is weighed and dissolved in methyl
sulfonic acid with certain concentration, stirred until completely
dissolved; then lithium hydroxide is added and stirred until
completely dissolved, at last an electrolyte is obtained. Methyl
sulfonic acid completely reacts with zinc oxide and lithium
hydroxide; zinc oxide reacts with methyl sulfonic acid to form
methyl sulfonic acid zinc, and lithium hydroxide reacts with methyl
sulfonic acid to form methyl sulfonic acid lithium.
Method IV: Metal Carbonate Reacts with Alkyl Sulfonic Acid
Appropriate amount of zinc carbonate is weighed and dissolved in
methyl sulfonic acid with certain concentration, stirred until
completely dissolved; then lithium hydroxide is added and stirred
until completely dissolved, at last an electrolyte is obtained.
Methyl sulfonic acid completely reacts with zinc carbonate and
lithium hydroxide; zinc carbonate reacts with methyl sulfonic acid
to form methyl sulfonic acid zinc, and lithium hydroxide reacts
with methyl sulfonic acid to form methyl sulfonic acid lithium.
A battery could be obtained by applying the electrolyte as
described above.
The battery comprises a cathode, an anode and an electrolyte; the
cathode comprises a cathode material, the cathode material
comprises a cathode active material which is capable of reversibly
intercalating-deintercalating the first metal ions: the electrolyte
is as described above.
The working principle of the battery may be summarized as follows:
during the charging process, the first metal ions in the cathode
active material deintercalate into the electrolyte, while, the
second metal ions in the electrolyte are simultaneously reduced and
deposited onto the anode as a second metal. During the discharging
process, the second metal is oxidized to the second metal ions and
existed in the electrolyte, the first metal ions in the electrolyte
intercalate into the cathode active material.
The cathode active material participates in the cathode reaction
which is capable of reversibly intercalating-deintercalating the
first metal ions.
Preferably the cathode active material is capable of reversibly
intercalating and deintercalating lithium ions, or sodium ions.
Specifically, the cathode active material has a spinel structure,
layered structure, or an olivine structure.
The cathode active material which is capable of intercalating and
deintercalating Li ions may comprise a spinel structure compound
having the general formula Li.sub.1+xMn.sub.yM.sub.zO.sub.k,
wherein -1.ltoreq.x.ltoreq.<0.5, 1.ltoreq.y.ltoreq.2.5,
0.ltoreq.z.ltoreq.0.5 and 3.ltoreq.k.ltoreq.6. M is selected from
at least one of the following: Na, Li, Co, Mg, Ti, Cr, V, Zn, Zr,
Si and Al. Preferably the cathode active material is
LiMn.sub.2O.sub.4. More preferably the cathode active material is
LiMn.sub.2O.sub.4 that has been doped, coated, or modified.
The cathode active material which is capable of intercalating and
deintercalating Li ions may comprise a layered structure compound
having the general formula
Li.sub.1+xM.sub.yM'.sub.zM''.sub.cO.sub.2+n, wherein
-1.ltoreq.x.ltoreq.0.5, 0.ltoreq.y.ltoreq.1, 0.ltoreq.z.ltoreq.1,
0.ltoreq.c.ltoreq.1 and -0.2.ltoreq.n.ltoreq.0.2. M, M' and M'' are
selected from at least one of the following: Ni, Mn, Co, Mg, Ti,
Cr, V, Zn, Zr, Si and Al. According to one embodiment, the cathode
active material comprises LiCoO.sub.2.
The cathode active material which is capable of intercalating and
deintercalating Li ions may comprise an olivine structure compound
having the general formula
Li.sub.xM.sub.1-yM'.sub.y(X'O.sub.4).sub.n, wherein
0<x.ltoreq.2, 0.ltoreq.y.ltoreq.0.6 and 1.ltoreq.n.ltoreq.1.5. M
is selected from Fe, Mn, V, and Co. M' is selected from at least
one of Mg, Ti, Cr, V and Al. X' is selected from at least one of S,
P and Si. According to one embodiment, the cathode active material
comprises LiFePO.sub.4.
In the current lithium battery industry, almost all cathode
materials are doped, coated or modified by various methods. However
these modifications may make the chemical formula of the material
more complex. For example, LiMn.sub.2O.sub.4 is no longer able to
represent the general formula of a "lithium manganese oxide" that
is widely used. Strictly speaking, the formula LiMn.sub.2O.sub.4
should include the spinel structure cathode materials of a variety
of modifications and be consistent with the general formula
Li.sub.1+xMn.sub.yM.sub.zO.sub.k. Similarly the chemical formula of
LiCoO.sub.2 and LiFePO.sub.4 described herein will be understood to
include the materials of a variety of modifications and to be
consistent with the general formula
Li.sub.xM.sub.1-yM'.sub.y(XO.sub.4).sub.n and
Li.sub.1+xM.sub.yM'.sub.zM''O.sub.2+n.
When the cathode active material is a lithium ion
intercalation-deintercalation compound, it can be selected from
LiMn.sub.2O.sub.4, LiFePO.sub.4, LiCoO.sub.2, LiM.sub.xPO.sub.4,
LiM.sub.xSiO.sub.y (where M is a metal with a variable valence) and
other compounds. When the cathode active material is a sodium ion
intercalation-deintercalation compound, it can be NaVPO.sub.4F.
When preparing a cathode slurry, a conductive agent and binder
should be added.
The conductive agent is selected from at least one of a conductive
polymer, active carbon, graphene, carbon black, graphite, carbon
fibre, metal fibre, metal powder or metal sheet. The aim to use the
conductive agent here is to reduce the overall resistance of the
cathode and enhance the conductive path of the cathode material
particles.
Preferably the conductive agent is graphite. To ensure graphite
with conductivity and stability and suppress corrosion of graphite
during charging process of battery, the particle size of graphite
is a key factor.
It is found that the smaller particle size makes the graphite with
the better conductive properties, but the poorer stability and
corrosion resistance; the larger particle size makes the cathode
material with the poorer conductive properties and higher internal
resistance, which result in a bad cycle life of battery. In the
present invention, the particle size of the conductive agent
graphite is less than 50 .mu.m. The conductive agent has a good
conductivity and corrosion resistance.
Preferably the crystallinity of the conductive agent graphite is no
less than 90% to ensure the graphite with an excellent thermal
stability and corrosion resistance.
Preferably the graphite comprises first graphite and second
graphite, the first graphite ranges in particle size from 15 to 50
.mu.m and the second graphite ranges in particle size from 5 to 15
.mu.m.
Graphite with different size in a certain proportion can greatly
improve the conductivity, rate capability and corrosion resistance
of the conductive agent, while suppress self-discharge of the
battery.
Graphite with small particle size can effectively increase the
contact area between the cathode active material and the conductive
agent graphite, which improves microscopic interface conductivity
of the cathode active material and the conductive agent graphite
and enhances compaction density and conductivity of the cathode
materials. Graphite with large particle size has a good corrosion
resistance and builds a solid and continuous conductive network.
Thus during charging process or float charging process, the
collapse of the conductive network and consumption of the
conductive agent could be avoided and the cycle life of the battery
could be significantly enhanced. Preferably the particle size of
the conductive agent graphite is greater than 0.5 .mu.m.
The first graphite with a particle size of 15-50 .mu.m is in the
range of 30-50% by weight; the second graphite with a particle size
of 5-15 .mu.m is in the range of 40-60% by weight; the remaining is
a graphite with a smaller particle size of 0.5-5 .mu.m. Graphite
with different size in a certain proportion builds a conductive
network with large contact area and good corrosion resistance,
which results in reduction of internal resistance, self-discharge
of the cathode active material and improvement of the battery float
charge life.
Preferably the particle size d10 of graphite is 6 .mu.m.
Controlling the content of graphite with small particle size could
enable graphite of better stability and corrosion resistance.
The addition of the conductive agent must reach a certain amount to
form a conductive network. Then voids in the structure of the
cathode active material are filled in with the conductive agent
particles and there will be effective contact between the
conductive agent and the cathode active material and between the
conductive agent and the conductive agent.
The content of the conductive agent is important; this may help the
cathode active material make full contact with the conductive agent
graphite particles to full contact and enable the interfacial
electrochemical reaction resistance to reach a stable value and
increase the stability of the cathode. Too much content of the
conductive agent will result in the low content of the cathode
active material in unit volume of the cathode. The density decrease
in the cathode active material will results in decrease in the
battery capacity. Too less content of the will results in the less
electronically conductive path in the cathode active material; this
may cause low utilization of the cathode active material, low
cathode capacity and poor cycle life of the battery.
To ensure that the cathode material has an excellent electrical
conductivity and high capacity, preferably the weight percentage of
the conductive agent graphite in the cathode material is 6-15%.
The binder is selected from one of polyethylene oxide,
polypropylene oxide, polyacrylonitrile, polyimides, polyesters,
polyethers, fluorinated polymers, polydivinyl polyethylene glycol,
polyethylene glycol diacrylate, polyethylene glycol dimethacrylate
and a combination thereof and derivatives. Preferably the binder is
polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or
styrene butadiene rubber (SBR).
In the present invention, it should be understood that the cathode
plate comprises the cathode active material, but not a cathode
current collector. In prior art the usual method to prepare cathode
is to coat slurry with a cathode active material on a cathode
current collector in a certain way and dry into a cathode. In this
process the whole cathode can only be weighed when sorting cathode.
Concerning uneven distribution of weight of cathode current
collector, the weight of cathode active material cannot be
accurately measured, thus cathode capacity will be different and
battery consistency and qualification rate will be affected. The
cathode plate could be prepared separately from cathode current
collector, which enables cathode active material to be weighed
solely. Thus the battery consistency is greatly improved and the
battery is easily assembled.
The cathode active material participates in electrochemical
reaction. The weight percentage of the cathode active material in
the cathode plate is 60-99%. In order to make the cathode have a
high capacity, the surface density range of the cathode active
material in the cathode plate is 200-2000 g/m.sup.2.
In one embodiment, the cathode plate also comprises a carrier which
is electrochemically inert. The cathode active material is formed
on the carrier. The carrier has two opposite surfaces. Without
limited, the cathode active material is formed on both surfaces of
the carrier or the cathode active material is formed on one surface
of the carrier.
Method of preparing the cathode plate is not particularly limited,
and in one embodiment, the method of preparing the cathode plate
comprises the following steps: preparing slurry containing a
cathode active material, and then forming the slurry on the
carrier. The cathode active material is formed on the carrier by
slurry method.
The role of the carrier which is electrochemically inert is to bear
the cathode active material. As known to person in art, the
electrochemically inert carrier does not participate in any
electrochemical reaction which is only in the presence of the
cathode plate to bear the cathode active material.
In one embodiment, the carrier has a porous structure and is
electrical insulation. The pore size range of the carrier is 50
meshes to 200 meshes, which ensure that the carrier has a certain
mechanical properties, the cathode active material could adhere to
the carrier and peeling resistance force of the cathode active
material and the carrier is improved. Thus the cathode plate could
stably works in the battery and it is easy for ions transporting in
the cathode active material.
In another embodiment, the carrier may conduct electron. The
material of the carrier comprises, but is not limited to,
conductive resin or metal.
Thickness of the carrier is not particularly limited, and in order
to ensure that the cathode plate has high energy density, the
thickness of the cathode plate should be controlled. Particularly
the thickness range of the cathode plate is 0.3.about.1.5 mm and
the thickness range of the carrier is less than 1 mm.
The carrier may be a non-woven fabric. The non-woven fabric is
processed by physical adhesive method without textile processing.
The composition of the non-woven fabric is not particularly limited
except for electrochemically inert. Non-woven fabric is low weight,
stable performance, easy finalizing design and low cost. In the
present invention, the application of non-woven fabric in
combination with the cathode active material in the cathode plate
could enable that the cathode plate has a lower weight and more
stable electrochemical performance.
The material of the carrier may be selected from at least one of
polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
polyethylene (PE), polypropylene (PP), polyamide (PA), polyurethane
(PU) and polyacrylonitrile (PAN). These materials can be stably
present in the cathode plate without participating in the
electrochemical reaction, thus the battery has a high energy
density output and low weight.
In prior art the usual method to prepare cathode is to coat slurry
with active material on a current collector. For example, in
lithium ion battery the slurry containing graphite is coated on a
copper foil to form an anode; in lead-acid batteries the lead paste
is coated on grid to form an anode. In this process the whole
electrode can only be weighed when sorting cathode. Concerning
uneven distribution of weight of cathode current collector, the
weight of cathode active material cannot be accurately measured,
thus cathode capacity will be different and the battery consistency
and qualification rate will be affected. In the present invention,
the ratio of the cathode active material, a binder and a conductive
agent in the cathode plate is accurate and consistent, and the
electrochemically inert carrier is a material with high
consistency, thus the weight consistency of the cathode plate is
very high.
The cathode further comprises a cathode current collector to bear
the cathode active material. The material of the cathode current
collector is selected from one of carbon-based material, metal or
alloy.
The cathode current collector is to conduct and collect electron
and does not participate in the electrochemical reaction. Within
the working voltage range of the battery, the cathode current
collector can be stably present in the electrolyte without
occurring side reaction, which ensures that the battery has a
stable cycle performance.
The cathode current collector needs to meet requirement of large
surface area and good mechanical properties. The cathode current
collector is preferably treated by passivating, punching, grinding
or weak acid corrosion treatment. The cathode current collector has
a large specific surface area after being treated, which may
improve compound degree of the cathode current collector and a
conductive film and reduce the contact resistance of the cathode
plate and combined current collector.
The main purpose of passivating the cathode current collector is to
form a passivated oxide film thereon, so that the cathode current
collector does not participate in electrochemical reaction during
the process of battery charging and discharging. This ensures the
stability of the battery. The method includes chemical or
electrochemical passivation.
Chemical passivation includes oxidization by an oxidizing agent.
The oxidizing agent should satisfy the requirement of making the
current collector form a passivation film without dissolving the
current collector. The oxidizing agent is selected from but not
limited to concentrated nitric acid and ceric sulphate
(Ce(SO.sub.4).sub.2).
Specifically the process of chemical passivation includes the
following steps: putting current collector in the oxidizing agent,
maintaining for 0.5-1 hours for formation of a passivation film and
then cleaning and drying the current collector.
The process of electrochemical passivation includes the following
steps: charging and discharging of the current collector or battery
with a current collector to form a passivation film thereon.
The current collector can be pre-passivated before battery
assembly. According to one embodiment, the current collector serves
as a working electrode charged and discharged in a three electrode
system with proper reference electrode and counter electrode. The
voltage for oxidizing the cathode current collector is 2.1-2.4V.
The cathode current collector can be a metal, such as aluminum or
an alloy (e.g. stainless steel or aluminum alloy). Of course, a two
electrode system could be utilized for passivation with the voltage
for oxidizing the cathode current collector at 2.1-2.4V.
The current collector can be passivated after battery assembly. The
cut-off voltage of charging and discharging are 2.1-2.4 V and
1.35-1.45V, the battery is charged and discharged no less than
once.
The thickness of the cathode current collector has a certain effect
on electrochemical properties of the cathode. Thin thickness will
affect the mechanical strength of the cathode current collector;
thick thickness will increase the weight of the cathode and affect
the energy density of the cathode. In the present invention the
thickness of the cathode current collector is preferably 10
.mu.m-100 .mu.m to make the battery have a high energy density
output.
Preferably a combined current collector is applied in the cathode.
The combined current collector further comprises a conductive film
coated on the cathode current collector. The conductive film should
comply with the following requirements: stable and insoluble in the
electrolyte, no swelling, no oxidization in high voltage, easy to
process into a dense, impermeable and electrically conductive film.
On the one hand, the conductive film could protect the cathode
current collector from being corroded by the electrolyte. On the
other hand, it helps to reduce the contact resistance between the
cathode current collector and the cathode plate and improve the
battery energy.
In order to enable most effective use of the conductive film, the
thickness of the conductive film need to be controlled. The
conductive film with thin thickness is easily damaged and
penetrated by the electrolyte and with bad uniformity; the
conductive film with thick thickness may affect its conductivity.
Preferably the thickness of the conductive film is 10 .mu.m.about.2
mm, thus the conductive film is able to effectively protect the
cathode current collector, reduce the contact resistance between
the cathode plate the cathode current collector and improve the
battery energy.
The cathode current collector has two opposite sides. Preferably
both sides of the cathode current collector are coated with the
conductive film.
The conductive film comprises a polymer as essential component. The
weight percentage of polymer in the conductive film is 50 to 95%.
Preferably the polymer is selected from thermoplastic polymer.
There are two possible ways to make the conductive film conductive:
(1) the polymer is a conductive polymer; (2) the conductive film
further comprises conductive filler.
The material of conductive polymer should be conductive and
electrochemically inert. Specifically the conductive polymer
includes, but are not limited to, polyacetylene, polypyrrole,
polythiophene, polyphenylene sulfide, polyaniline,
polyacrylonitrile, polyquinoline, polyparaphenylene and mixtures
thereof. The conductive polymer itself could be conductive, and the
conductive polymer could be doped or modified to further improve
its conductivity. The conductive polymer is preferably polyaniline,
polypyrrole, polythiophene and polyacetylene in view of
conductivity and stability.
The material of the conductive filler should satisfy the
requirements of small surface area, difficult oxidation, high
crystallinity, good conductivity but electrochemically inert.
The material of the conductive filler includes, but is not limited
to conductive polymer, carbon based materials or metal oxides. The
weight percentage of the conductive filler in the conductive film
is 5 to 50%. The average particle size of the conductive filler is
not particularly limited, usually in the range of 100 nm to 100
nm.
Preferably the conductive filler is a carbon-based material. The
shape or mechanical property of the carbon-based material is not
specifically limited, for example, the carbon-based material is
selected from one of graphite, carbon nanotubes or amorphous
carbon. Amorphous carbon includes but is not limited to activated
carbon and carbon black. The carbon-based material is preferably
carbon black and graphite, which has a large potential window, thus
the carbon-based material can be stable and of high conductivity
within a wide range of the cathode and anode electric potential.
Metal oxides includes but is not limited to lead oxide and tin
oxide.
When the conductive film comprises the conductive filler, the
polymer of the conductive film preferably comprises a
non-conductive polymer which plays a role in combining the
conductive filler. The non-conductive polymer could enhances the
binding of electrically conductive filler, improves the reliability
of the battery. Preferably the non-conductive polymer is a
thermoplastic polymer.
The thermoplastic polymer includes, but is not limited to
polyolefin such as at least one of polyethylene, polypropylene,
polybutene, polyvinyl chloride, polystyrene, polyamide,
polycarbonate, polymethyl methacrylate, polyoxymethylene,
polyphenylene ether, polysulfone, polyether sulfone,
styrene-butadiene rubber and polyvinylidene fluoride, wherein the
thermoplastic polymer preferably is polyolefin, polyvinylidene
fluoride or polyamide. These polymers are easily melted to compound
together with the cathode current collector and the cathode plate.
In addition, these polymers have a large potential window, so that
the cathode can be more stable and the battery has a low weight and
high density output.
The conductive film can be formed by means of preparing a slurry
containing the thermoplastic polymer, coating and solidifying the
slurry. Of course the conductive filler can be included in the
slurry. Specifically speaking, the thermoplastic polymer monomer
and the conductive filler are mixed in a certain composite mode to
obtain a conductive film with conductivity, such as dispersion
composite mode, hierarchy composite mode. The thermoplastic polymer
monomer is a small molecule, the conductive filler can be well
dispersed in the thermoplastic polymer monomer, and then under
initiator the thermoplastic polymer monomer occur polymerization
reaction to obtain a conductive film.
The conductive film is coupled to the cathode current collector by
hot pressing, vacuum pumping or spraying.
Hot pressing is to heat a polymer contained in the conductive film
under temperature which is higher than the glass transition
temperature of the polymer. The polymer is softened and can be
adhered to the cathode current collector under a certain pressure.
The pressure is to make the binding closely between the conductive
film and the cathode current collector.
In one embodiment of vacuum pumping, the conductive film is
produced to a trilateral sealed bag with a predetermined size, then
cut a good positive current collector placed on the conductive film
bag, by vacuuming, sealing a way that the conductive film close
coated on the cathode current collector.
In one embodiment of spraying, slurry containing a thermoplastic
polymer is prepared, and then the slurry is evenly sprayed on a
cathode current collector, cooled and solidified. And then the
cathode current collector is coated with a layer of conductive
film.
In prior art the usual way to prepare an electrode comprises the
following steps: coating a slurry containing an electrode active
material on a current collector in a certain way. The present
invention provides a battery, in the preparation of the cathode,
the cathode plate may be coupled to the combined current collector
by hot pressing or binding, thus the preparation of the battery can
be simplified and production efficiency can be improved. The
conductive film formed between the cathode plate and the cathode
current collector could reduce the contact internal resistance
between the cathode plate and the cathode current collector. The
battery has a good consistency.
The second metal ion and the second metal participate in
electrochemical reaction in the anode of the battery. The second
metal can be oxidized to the second metal ion and the second metal
ion can be reversibly reduced and deposited as the second
metal.
Preferably the anode also comprises an anode additive which
includes a bismuth compound. The way of addition of the bismuth
compound to the anode depends on the anode, which may be selected
from physical method and chemical method. The physical method
includes but is not limited to a suspension coating method, vacuum
deposition, magnetron sputtering; the chemical method included
electrochemical plating.
In a first preferred embodiment, the anode is an anode current
collector which serves as a carrier of electronic conduction and
collection but does not participate in the electrochemical
reaction. In this embodiment, a bismuth compound is added to the
anode by means of dispersing a bismuth compound to a dispersant,
the resulted dispersion being coated on the anode current
collector, and then removing the dispersant.
The material of the anode current collector may comprise at least
one metal selected from Ni, Cu, Ag, Pb, Mn, Sn, Fe, Al or a
passivated metal thereof, or silicon or a carbon based material.
The carbon based material includes graphite materials, such as
commercial graphite pressed foil, wherein graphite weight rate is
in the range 90-100%. The material of the anode current collector
can be stainless steel or passivated stainless steel. Similarly the
mode of stainless steel can be but is not limited to 300 series
stainless steel, such as stainless steel 304, 316 or 316L.
In addition, the material of the anode current collector can be
selected from a metal with an electroplating layer or coating layer
of high hydrogen potential, which is selected at least one of C,
Sn, In, Ag, Pb, Co, or an alloy or oxide thereof. The thickness
range of the electroplating layer or coating layer is 1-1000 nm,
such as copper or graphite foil coated with tin, lead or
silver.
In a second preferred embodiment, the anode comprises an anode
current collector and an anode active material.
The anode active material is the second metal. Preferably the anode
active material is selected from one of Zn, Ni, Fe, Cr, Cu, Mn, Sn
or Pb.
If the second metal ion in the electrolyte is Zn.sup.2+, the
corresponding anode active material is metal Zn. For example, the
anode comprises brass foil and zinc foil, brass foil serves as the
anode current collector, zinc foil serves as the anode active
material which participates in the anode reaction.
The anode current collector is as described in the first preferred
embodiment.
The second metal is in form of sheet or powder.
When a second metal sheet is used as the anode active material, the
second metal sheet and the anode current collector form a composite
layer.
In this case, the method of adding a bismuth compound to the anode
includes but is not limited to the following steps: dispersing the
bismuth compound to a dispersant, the resulted dispersion being
coated on the second metal sheet, and finally removing the
dispersant.
When a second metal powder is used as the anode active material,
the method of adding a bismuth compound to the anode includes but
is not limited to the following steps: mixing the bismuth compound
and the second metal powder to prepare a slurry, then the slurry
being coated on the anode current collector to form an anode.
When preparing an anode, except for the anode active material (i.e.
the second metal powder) an anode conductive agent and anode binder
could be added to enhance the performance of the anode.
In a third preferred embodiment, the second metal sheet is used as
the anode, which serves as an anode current collector and anode
active material.
In this case, the method of adding a bismuth compound to the anode
includes but is not limited to the following steps: dispersing the
bismuth compound to a dispersant, the resulted dispersion being
coated on the second metal sheet, and finally removing the
dispersant.
Of course, a bismuth compound can be added to the anode and the
electrolyte in order to make the battery performance more
excellent.
Preferably the bismuth compound is selected from bismuth trioxide
and/or bismuth nitrate.
Preferably the amount of a bismuth compound in the anode is as
follows:
When bismuth trioxide is used alone, the weight percentage of
bismuth trioxide in the anode is 0.1 to 10%.
When bismuth nitrate is used alone, the weight percentage of
bismuth nitrate in the anode is 0.1 to 10%.
Of course a mixture of bismuth trioxide and bismuth nitrate can
both used.
Preferably the anode may also comprise an anode modifier. The anode
modifier is attached to the anode surface, which is different from
the electrolyte. When the anode modifier is attached to the surface
of the anode, the anode modifier is preferably coated on the
surface of the anode to form a coating layer, i.e., the negative
modifier is included in the coating layer. Specifically speaking
the coating method is as following: dispersing the anode modifier
to dispersion, the resulted dispersion being coated directly on the
surface of the anode, and then drying.
Preferably the weight percentage of the anode modifier in the
dispersion is less than 20%, which makes coating operation easy and
improves the coating effect.
Preferably the thickness of the coating layer is 5-40 .mu.m, which
can effectively void the reduction of the ion transport
efficiency.
More preferably the coating layer further comprises the second
metal ion, namely, the anode modifier and the second metal ion salt
are together coated on the anode surface. Specifically speaking,
the anode modifier and the second metal ion salt are dispersed in a
dispersant to form a dispersion, which is coated on the surface of
the anode and dried thereafter.
The addition of the second metal ion in the coating layer can
effectively improve the conductivity of the second metal ion. When
the coating layer comprises a second metal ion, the thickness of
the coating layer is preferably 20-1000 .mu.m.
The attachment of the anode modifier to the anode surface could
effectively inhibit the generation of dendrites, enhance the safety
performance of the battery, improve the cycle performance of the
battery, suppress the side reaction between the electrolyte and the
anode and avoid the anode gas production.
A separator can be excluded in the battery. Of course considering
the safety performance of the battery, a separator is preferably
configured between the cathode and the anode. The separator could
avoid short circuit of cathode and anode caused by other unforeseen
factors.
Separator has no special requirements, as long as it allows the
electrolyte passing and is electron insulation. Various organic
lithium-ion battery separators can be useful in the present
invention. The separator may also be porous ceramic separator and
other material.
Bipolar Battery
The present invention also provides a battery. Particularly, the
battery is an aqueous bipolar battery, which may be introduced by
following specific embodiments.
Embodiment 1
FIG. 1 shows schematically the bipolar battery in a first
embodiment. The battery 20 comprises a cathode 22, at least one
bipolar electrode 24, an anode 26 and an electrolyte 28. The
cathode 22, bipolar electrode 24 and the anode 26 are stacked, the
cathode 22 and the anode 26 are located at the top layer and lowest
layer, the bipolar electrode 24 and an electrolyte 28 are
configured between the cathode 22 and the anode 26. Specific to
FIG. 1, the battery 20 comprises two bipolar electrodes 24.
The cathode 22 comprises a cathode collector 30 and a cathode plate
23 which is formed on one surface of the cathode collector 30. The
cathode plate 23 comprises a cathode active material 50 which is
capable of reversibly intercalating-deintercalating a first metal
ions. In embodiment 1 the cathode plate 23 further comprises an
electrochemically inert carrier 2; the cathode active material 50
is formed on the carrier 2.
The cathode current collector 30, the cathode active material 50,
the first metal ion and the carrier 2 may be as described
previously.
FIG. 2 is a schematic cross-sectional view of bipolar electrode 20.
The bipolar electrode 24 comprises a bipolar current collector 32
and the cathode plate 23. The bipolar current collector 32 has two
opposite surfaces which are a first surface 321 and a second
surface 322, the cathode plate 23 is formed on the first surface
321. The polarity of the first surface 321 and the second surface
322 are opposite; specifically speaking the first surface 321 is
served as cathode and a second surface 322 is served as anode.
The cathode plate 23 is attached to the bipolar current collector
32 through a certain way, such as laminating, pressing, bonding or
hot pressing. The carrier 2 and the cathode active material 50 of
the cathode plate 23 may be as described previously.
The material of the bipolar current collector 32 may be a
conductive plastic; preferably the thickness range of bipolar
current collector 32 is 50 to 100 .mu.m.
The material of conductive plastic is selected from a conductive
polymer, which includes but is not limited to at least one of
polyacetylene, polypyrrole, polythiophene, polyphenylene sulfide,
polyaniline, polyquinoline or polyphenylene. Conductive polymer
itself has conductivity, but it can also be doped or modified to
further improve its conductivity.
Conductive plastic may also be a compound conductive plastic which
comprises a polymer as main substrate and a conductive agent. The
conductivity of the compound conductive plastic is mainly realized
by the conductive agent, so it is not particularly limited of the
polymer that whether it is conductivity. Specifically conductive
plastic comprises a polymer and a conductive agent; the polymer
includes, but is not limited to at least one of polyethylene,
polypropylene, polybutene, polyvinyl chloride, polystyrene,
polyamide, polycarbonate, polymethyl methacrylate,
polyoxymethylene, polyphenylene ether, polysulfone, polyether
sulfone, styrene-butadiene rubber or fluorine resin; the polymer
may be a polytetrafluoroethylene or its copolymer, such as
polytetrafluoroethylene (PTFE) and styrene-butadiene rubber (SBR)
copolymer.
Conductive agent includes carbon-based material, metal or metal
oxide. The weight percentage range of conductive agent in the
conductive plastic is 10-90%.
Carbon-based material is selected from one of graphite, carbon
nanotubes and amorphous carbon. Amorphous carbon includes but is
not limited to activated carbon and carbon black.
The form of metal may be metal powder, metal foil, metal wire or
metal fiber. Metal oxides include, but are not limited to lead
oxide and tin oxide.
Specifically the polymer and a conductive agent are processed by a
certain composite mode to obtain a plastic with conductivity, such
as dispersion composite mode and hierarchy composite mode.
The material of bipolar current collector 32 may also be passivated
stainless steel or stainless steel. The mechanical properties of
stainless steel is superior to conductive plastic, therefore, when
stainless steel is used as a bipolar current collector 32, the
thickness of the bipolar current collector 32 may be thinner,
specifically the thickness of the bipolar current collector 32 is
20-100 .mu.m.
Passivation treatment method of stainless steel is not limited; it
may be a physical method, chemical method or electrochemical
method. The main purpose of passivation is to improve the
compatibility of the bipolar current collector 32 and the
electrolyte 28 and reduce side reaction, which enable that the
battery has a stable cycle performance.
Requirement on the mechanical properties of the bipolar current
collector 32 is not restrict. A lightweight conductive plastic or a
thin stainless steel may be employed as a bipolar current collector
32. Thus the overall weight of the battery 20 is reduced, and the
energy density of the battery 20 could be significantly
improved.
The anode 26 is selected from metal, alloy or carbon-based
material.
Specifically the anode 26 comprise at least one metal selected from
Zn, Ni, Cu, Ag, Pb, Mn, Sn, Fe, Al or a passivated metal thereof or
an alloy containing metal thereof or graphite foil, graphite sheet,
carbon cloth, carbon felt, carbon fibers or tinned copper or
brass.
Specifically the anode 26 can be selected from a metal with an
electroplating layer or coating layer of high hydrogen potential,
which is selected at least one of C, Sn, In, Ag, Pb, Co, or an
alloy or oxide thereof. The thickness range of the electroplating
layer or coating layer is 1-1000 nm, such as copper or graphite
foil coated with tin, lead, silver or carbon. The thickness range
of the cathode current collector 30 and the anode 26 is 1-10
mm.
The anode 26 may be as described previously, i.e., the anode 26 is
served as an electron collection and conduction substrate and not
involved in the electrode reaction or the anode 26 includes an
anode current collector and an anode active material, such as the
anode 26 comprises brass foil and zinc foil, zinc foil is the anode
active material.
Electrolyte 28 is sandwiched between the cathode 22 and the anode
26. The cathode 22, the bipolar electrode 24 and the anode 26 is
stacked. When the battery 20 comprises only one bipolar electrode
24, the electrolyte 22 is sandwiched between the cathode 22 and the
bipolar electrode 24, and between the anode 26 and the bipolar
electrode 24. When the battery 20 comprises more than one bipolar
electrode 24, the electrolyte 22 is sandwiched between the cathode
22 and the adjacent bipolar electrode 24, between the adjacent
bipolar electrodes 24 and between the anode 26 and the bipolar
electrode 24.
Electrolyte 28 has already been described previously and no more
repeated.
Preferably the battery 20 further comprises an anode additive which
is added to the anode 26 and/or 28 in the electrolyte 28. The anode
additive is bismuth trioxide and/or bismuth nitrate.
Preferably the battery 20 further comprises an anode modifier which
is added to the anode 26 and/or 28 in the electrolyte 28. The anode
modifier is selected from at least one of gelatin, agar, cellulose,
cellulose ethers and soluble salts thereof, dextrin and
cyclodextrin.
Similarly the addition method of the anode additive and the anode
modifier has been introduced previously, no more repeated here.
In embodiment 1 the battery 20 further includes a separator 34 to
retain the electrolyte 28 and prevent the battery 20 from short
circuit. The separator 34 is sandwiched between the cathode 22 and
the adjacent bipolar electrode 24, between the adjacent bipolar
electrodes 24 and between the anode 26 and the bipolar electrode
24.
Separator 34 may be selected from a porous membrane, non-woven
fabric or glass fiber. Porous membrane includes, but is not limited
to one of polyethylene (PE), polypropylene (PP), polyimide or
PE-PP, PP-PE-PP laminate membrane. Non-woven fabric includes, but
is not limited to rayon, cellulose acetate and nylon. The amount of
electrolyte 28 retained in the separator 34 may be in the range of
retention of the separator 34 or beyond the range, because the
battery 20 is configured with a seal part 36 to avoid leakage of
the electrolyte 28.
The seal part 36 is formed and arranged at the outer circumference
part of a part of the bipolar current collector 32. Without
particularly limited the seal ring may be used as the seal part 36.
Preferably the seal ring is in a rectangular shape. The material of
seal ring meets requirement of with an excellent sealing effect
under the environment of the battery 20.
The material of the seal part 36 is a rubber which is selected
from, but not limited to one of silicone rubber, fluorine rubber,
alkene rubber and nitrile rubber. Alkene rubber includes, but is
not limited to styrene butadiene rubber (SBR) and chloroprene
rubber (CR). These rubber-based resins have a good seal ability
(liquid tightness), acid and alkali resistance, chemical
resistance, durability, weather resistance and heat resistance, and
can maintain an excellent performance in a long-term use of the
battery without deteriorating. Thus it is possible to effectively
prevent the electrolyte 28 leaking from the battery 20, prevent the
battery 20 from short-circuit due to the leakage of electrolyte 28
and ensure cycle stability of the battery 20.
When a seal ring is used as the seal part 36, the area of the
separator 34 is smaller than the area of the sealing ring and the
height of the seal ring is no less than the thickness of the
separator 34 and the cathode plate 23. When assembling the battery,
the separator 34 retaining the electrolyte 28 is placed in the
circle of the seal ring and not involved in sealing, which could
avoids the leakage of the electrolyte 28 because of using a porous
membrane. Of course the area of the separator 34 may be greater
than the area bounded by the seal part 36, and in this case the
separator 34 and the seal part 36 are integrally formed and the
electrolyte 28 cannot be leaked from the battery.
As shown in FIG. 3, the bipolar electrodes 24 are stacked between
the cathode 22 and the anode 26; electrons are export or import
only from the cathode 22 and anode 26. The battery 20 comprises
three battery cells 38 connected in series. Each cell 38 comprises
the cathode, the anode, the electrolyte and the separator.
Electrolyte 28 is sealed by the seal part 36, which avoid
short-circuit between the battery cells 28 due to the leakage of
the electrolyte 28 and ensure the normal operation of the battery
20.
For example, the battery cell 38 comprises the cathode current
collector 30, the cathode plate 23, the separator 34, the
electrolyte 28, the seal part 36 and the second surface of the
bipolar electrode which is served as anode. The seal part 36 is to
seal the electrolyte in each cell 38 to avoid short circuit of the
battery 2 caused by leakage of electrolyte 28. The battery only
comprises two bipolar electrodes 24 in FIG. 3, but in fact it can
be easily to adjust the number of the bipolar electrode 20 in
accordance with usage requirements to prepare a battery having
different output voltage and a battery having a high output
voltage. The present invention provides a battery having a wide
range of uses.
The preparation process of the battery is simple. Particularly a
rectangular seal ring is stacked on the outer peripheral portion of
an anode; a separator retaining electrolyte is placed within the
seal ring; and then a bipolar electrode and a cathode are
sequentially stacked thereon. The cathode active material in the
cathode and the bipolar electrode is facing to the anode and the
electrolyte is sealed by the ring seal. The number of bipolar
electrode determines the final output voltage of the battery; it is
possible to adjust the number of bipolar electrode according to the
usage requirement. The battery has a wide range of uses.
In order to prevent external shock and deterioration of the
environment the laminated and sealed battery is all sealed by an
encapsulating material or housing. Encapsulating material or
housing material is preferably a metal material coated with a
polymer, such as a metal coated with a polypropylene film. The
metal includes, but is not limited to aluminum, stainless steel,
nickel or copper.
As shown in FIG. 4, the working principle of the aqueous bipolar
battery 20 may be summarized as follows: in a battery cell 38
during the charging process, the first metal ions in the cathode
active material 50 of the cathode plate 23 deintercalate into the
electrolyte, while, the second metal ions in the electrolyte are
simultaneously reduced and deposited onto the second surface 322 of
the bipolar current collector 32 to be an anode active material. In
a battery cell 38 comprising an anode 26, the second metal ions in
the electrolyte are reduced and deposited onto the anode 26.
Discharge process is the reverse process.
In the present invention, the first surface 321 of the bipolar
current collector 32 are formed with the cathode plate 23, the
second surface 322 of the bipolar current collector 32 is served as
a anode to provide a substrate for reduction and deposition of the
second metal ion, the second metal ions are in the electrolyte.
Comparing to a bipolar current collector in prior art of which the
first face and second face are all disposed with an electrode
active material, the battery provide in the present invention is
more compact and has an excellent energy density and power density.
In addition the battery using an aqueous electrolyte is safer and
more environmentally friendly comparing to commercial lithium-ion
batteries using organic electrolyte.
The bipolar battery 20 in the present invention has a plurality of
battery cells 38 in series. Each cell 38 is well sealed by the seal
part 36, thereby preventing a short circuit due to leakage of the
electrolyte 28. Further even without a special leak-proof member or
insulating member, short circuit of the battery cell 38 can be
prevented. The bipolar battery 20 has excellent ion conductivity,
charge and discharge characteristics. In addition, the bipolar
battery has different output voltages by using different number of
the bipolar electrode 24 according to the usage requirement.
Embodiment 2
As shown in FIG. 5, the embodiment 2 provides a battery 100
comprising the cathode 40, at least one bipolar electrode 24, the
anode 26 and the electrolyte 28. Bipolar electrodes 24 are stacked
between the cathode 40 and the anode 26. The cathode 40 and the
anode 26 are located in the uppermost layer and the lowermost
layer.
Which is different from the embodiment 1 is that the cathode 40 in
embodiment 2 comprises a combined current collector and a cathode
plate 23 which is formed on one surface of the combined current
collector. The combined current collector comprises a cathode
current collector 30 and a conductive film 12 which is coated on
the cathode current collector 30.
The conductive film 12 may be coated on one or both surfaces of the
cathode current collector 30 by vacuum pumping, hot pressing or
spraying. The thickness of the conductive film 12 is 0.01-0.2 mm.
Both surfaces of the cathode current collector 30 are coated with a
conductive film 12 in FIG. 5.
Material of the conductive film 12 has also been described in
detail previously and not repeated here.
On the one hand, the conductive film 12 could reduce the contact
resistance between the cathode current collector 30 and the cathode
plate 23; On the other hand, it helps to protect the cathode
current collector 30 from being corroded by the electrolyte 28,
ensure the stability of the cathode current collector 30, improve
the self-discharge of the battery and make the battery have a
stable cycleability.
As shown in FIG. 6, the battery unit 38 is sealed by the seal part
36 which is formed and arranged at the outer circumference part of
a part of the bipolar current collector 32.
The remaining construction and assembly way of battery 100 are the
same as in Embodiment 1 which may not be repeated here.
The battery 100 in embodiment 2 comprises a cathode current
collector 30 coated with a conductive film 12, which prevent
potential corrosion problems of cathode current collector 30 in the
electrolyte 28. So the battery 100 has the characteristic of high
output voltage, safety, environmental protection and stable
cycleability.
Embodiment 3
As shown in FIG. 7, the embodiment 3 provides a battery 200
comprises the cathode 22, at least one bipolar electrode 24, the
anode lead 26 and the electrolyte 28. Bipolar electrodes 24 are
stacked between the cathode 22 and the anode 26. The cathode 40 and
the anode 26 are located in the uppermost layer and the lowermost
layer.
Which is different from the embodiment 1 is that the battery does
not include a separator.
Similarly, the battery unit is sealed by the seal part 36 which is
formed and arranged at the outer circumference part of a part of
the bipolar current collector 32. For example, seal ring may be
employed as the seal part 36. The height of the seal ring is
greater than the thickness of the cathode plate 23. There are a
certain distance between the cathode 22 and adjacent bipolar
electrode 24, between the bipolar electrode 24 and adjacent anode
24 through the seal ring having a certain height, which could avoid
short-circuit of the battery. When the number of bipolar electrode
24 is more than one, the adjacent bipolar electrodes 24 are also
sealed with the seal part 36.
The preparation of the battery 200 in embodiment 3 comprises the
following steps. A cathode 22, a bipolar electrode 24 and an anode
26 are stacked and sealed. Specifically the cathode plate 24 of the
cathode 22 and the cathode plate 24 of the bipolar electrode 23 are
arranged facing to the anode 26. A rubber material such as seal
ring having a higher thickness than the cathode plate 23 could be
used as the seal part 36. The seal ring is formed and arranged at
the outer circumference part of a part of the bipolar current
collector 32. And finally through the injection the electrolyte 28
is added.
The seal part 36 may also be a thermoplastic rubber material. In
the initial sealing the thermoplastic rubber material is formed and
arranged at trilateral outer circumference part of the bipolar
current collector 32. After being arranged of the cathode 22, the
bipolar electrode 24 and the anode 26, the thermoplastic rubber are
solidified by heating or hot pressing, and then the electrolyte 28
is injected through unsealed outer circumference part of the
bipolar current collector 32 and then all battery units are
completely sealed.
The remaining construction and assembly way of battery 200 are the
same as in Embodiment 1 which may not be repeated here.
The battery 200 in embodiment 3 does not include a separator. The
battery 200 can work properly and continuously and has a lighter
weight. So the battery 200 has superior energy density and specific
power. In addition, in the preparation of the battery 200, it can
be easily to form the seal part 36 to prevent short-circuit due to
the electrolyte leakage 28. Battery 200 has excellent cycleability
and cycle life.
Embodiment 4
As shown in FIG. 8, the embodiment 4 provides a battery 300
comprises the cathode 22, at least one bipolar electrode 24, the
anode lead 26 and the electrolyte 28. Bipolar electrodes 24 are
stacked between the cathode 22 and the anode 26. The cathode 40 and
the anode 26 are located in the uppermost layer and the lowermost
layer.
Which is different from the embodiment 1 is that the battery 300
does not include a separator.
In embodiment 4, the conductive film 12 coated on the cathode
current collector 30 avoid the cathode current collector 30 in
contact with the electrolyte 28, which improves the stability of
the cathode current collector 30 and cycleability of the battery
300. The battery 300 without a separator is much lighter, easy to
carry and has an excellent performance.
A lightweight conductive plastic or a thin stainless steel may be
employed as a bipolar current collector in the present invention.
Thus the battery can work normally and has a lighter weight. The
battery has obvious advantages in energy density and volume.
Secondly, the electrolyte used in the battery has a relatively
higher ion conductivity, which improves rate performance of the
battery. In the manufacturing process, according to usage
requirements the battery could be altered to output different
voltages. The battery is safe, environmental protection, easy to
produce and used in industrial application.
The present invention provides a battery comprising at least one
bipolar electrode. Only one surface of the bipolar current
collector is formed with a cathode plate. The second surface of the
bipolar current collector has no anode active material before the
initial charge and discharge. The second metal ions in the
electrolyte are deposited on the second surface of the bipolar
current collector when the battery is charged. The battery using an
aqueous electrolyte is much safer and environmental friendly
comparing to lithium ion battery using organic electrolyte. In
addition, by setting the number of bipolar electrode the battery
with different output voltage or high output voltage can be
prepared. The battery has a wide scope of applications and can be
easily prepared.
Battery with an Internal Parallel Structure
The present invention also provides a battery. Particularly, the
battery has an internal parallel structure, which may be introduced
by following specific embodiments.
Embodiment 5
As shown in FIG. 9, the embodiment 5 provides a battery 400
comprising a cathode 42, two anodes 44 and an electrolyte 28. The
cathode 42 is sandwiched between two anodes 44. The electrolyte 28
is sandwiched between the cathode 42 and the anode 44.
The cathode 42 comprises a combined current collector and a cathode
plate 23 which is formed on one surface of the combined current
collector. The combined current collector comprises a cathode
current collector 30 and a conductive film 12 which is coated on
the cathode current collector 30. The cathode plate 23 comprises a
cathode active material 50 which is capable of reversibly
intercalating-deintercalating a first metal ions.
The combined current collector has two opposite surfaces and the
cathode plates 23 are disposed on the both surfaces of the combined
current collector.
The cathode plate 23 includes an electrochemically inert carrier,
the cathode active material 50 is formed on the carrier, the
cathode active material 50 and the carrier has been introduced
previously and not repeated here.
As shown in FIG. 9, preferably both surfaces of the cathode current
collector 30 are coated with conductive film 12. Then, the cathode
plate 23 is coupled to the conductive film 12 of the combined
current collector by means of hot pressing, bonding, laminating or
pressing.
The conductive film 12 may be coated on the cathode current
collector 30 by vacuum pumping, hot pressing or spraying. For
example, the cathode current collector 30 is placed between two
sheets of conductive film 12; then the conductive film 12 is coated
and attached to the cathode current collector 30 by heating. The
parts of the conductive film 12 that is beyond the cathode current
collector 30 are well sealed. The thickness of one sheet of the
conductive film 12 is 10-200 .mu.m.
The conductive film has been described in detail previously and not
repeated here.
The anode 44 is selected from metal, alloy or carbon-based
material.
Specifically the anode 44 comprise at least one metal selected from
Zn, Ni, Cu, Ag, Pb, Mn, Sn, Fe, Al or a passivated metal thereof or
an alloy containing metal thereof or graphite foil, graphite sheet,
carbon cloth, carbon felt, carbon fibers or tinned copper or
brass.
Electrolyte 28 has already been described previously and no more
repeated.
The main difference of battery 400 and battery 20 is that battery
400 has an internal parallel structure. Therefore, the basic
component of battery may not be described here.
In embodiment 5 the battery 400 further includes a separator 34 to
retain the electrolyte 28 and prevent the battery 400 from short
circuit. The separator 34 is sandwiched between the cathode 42 and
the anode 44. Specifically the anode 44, the separator 34, the
cathode 42, separator 34 and negative 44 are stacked and placed in
a package housing. The electrolyte is retained in the separator 34
to ensure the ion conduction path between the cathode 42 and the
anode 44.
Separator 34 may be selected from a porous membrane, non-woven
fabric or glass fiber. Porous membrane includes, but is not limited
to one of polyethylene (PE), polypropylene (PP), polyimide or
PE-PP, PP-PE-PP laminate membrane. Non-woven fabric includes, but
is not limited to rayon, cellulose acetate and nylon. The amount of
electrolyte 28 retained in the separator 34 may be in the range of
retention of the separator 34 or beyond the range, because the
battery 20 is configured with a seal part 36 to avoid leakage of
the electrolyte 28.
In order to prevent external shock and deterioration of the
environment the laminated and sealed battery 400 is all sealed by
an encapsulating material or housing. Encapsulating material or
housing material is preferably a metal material coated with a
polymer, such as a metal coated with a polypropylene film. The
metal includes, but is not limited to aluminum, stainless steel,
nickel or copper.
As shown in FIG. 10, the cathode 42 is disposed between the anodes
44. Two anodes 44 share the cathode 42. Electrons are exported or
imported from the cathode current collector 30 and the anode 44.
The battery 400 has two battery units 46 in parallel. Each battery
unit 46 has a cathode 42, an anode 44, an electrolyte 28 and
separator 34 which retains the electrolyte 28. Since the battery
unit 46 is connected in parallel, the electrolyte 28 may be in any
battery unit 46 without causing short circuit. The battery 400 can
work normally and stably.
Comparing to battery comprising separate battery unit connected in
parallel, the battery 400 provided in present invention uses only
one cathode 42 to make battery units 46 connect in parallel. Two
anodes 44 share one cathode 42. Both surfaces of the cathode
current collector 30 are used to be coupled with the cathode plate
23, which not only save the cathode material, but also make the
battery more compact and lighter. Therefore the battery 400 has an
excellent energy density and power density. Finally, the battery
400 using the aqueous electrolyte 28 is safer and more
environmentally friendly comparing to the current commercial
lithium-ion batteries using organic electrolyte.
The preparation process of the battery 400 is simple which can be
prepared by laminating. Specifically, the anode 44, the separator
34 impregnated with the electrolyte 28, the cathode 42 and the
anode 44 are arranged in a fixed sequence and packaged. Battery 400
has two battery units 46 connected in parallel. Seal part is no
need here to seal the battery units 46. The battery 400 with an
internal parallel structure can work normally and stably and has an
excellent charge-discharge characteristic, higher output capacity
and wide scope of applications.
Embodiment 6
As shown in FIG. 11, the embodiment 6 provides a battery 500
comprising two cathodes 42. an anode 44 and an electrolyte 28. The
anode 44 is sandwiched between two cathodes 42 and two cathodes 42
share the anode 44. The electrolyte 28 is sandwiched between the
cathode 42 and the anode 44.
The material and preparation method of the cathode, anode and the
electrolyte are the same as that in embodiment 5, there will be no
more description.
Both batteries in embodiment 5 and 6 have two battery units
connected in parallel. The difference is that in embodiment 5 the
battery 400 has two anodes 44 sharing a cathode 42 and in
embodiment 6 the battery 500 has two cathodes 42 sharing an anode
44. Therefore the structure of the battery in the present invention
can be multiple according to the production process, the weight of
cathode and anode, material costs and other factors. The obtained
battery finally has advantages of low cost and excellent
performance.
Batteries in embodiment 5 and 6 have an internal parallel
structure. Compared to battery with parallel structure in prior
art, the battery is more material saving, compact, lightweight and
has obvious advantages in energy density and volume; secondly, the
battery using the aqueous electrolyte which has high ion
conductivity is safer and more environmentally friendly; finally, a
battery with different output capacity could be prepared according
to usage requirement. The battery has wide scope of
application.
Embodiment 7
The embodiment 7 provides a battery 600 comprising a cathode 42, an
anode 44 and an electrolyte 28.
The cathode 42 comprises a combined current collector and a cathode
plate 23. The combined current collector comprises a cathode
current collector 30 and a conductive film 12 which is coated on
the cathode current collector 30. The cathode plate 23 comprises a
cathode active material 50 which is capable of reversibly
intercalating-deintercalating a first metal ions. The combined
current collector has two opposite surface and the cathode plate 23
is coupled to at least one surface which faces to the anode. The
cathode 42 have been described previously and no more repeated
here.
Battery comprises n pair of cathodes and anode, wherein n.gtoreq.2.
The cathodes and anode are arranged alternately. Two adjacent
cathodes 42 share an anode 44 located between these two adjacent
cathodes 42 and two adjacent anodes 44 share a cathode 42 located
between these two adjacent anodes 44. Specific to FIG. 12, the
battery 600 includes two pairs of cathode 42 and anode 44.
The cathode plate 23 further comprises an electrochemically inert
carrier in embodiment 7. The cathode active material 50 is formed
on the carrier.
Anode and electrolyte have also been introduced in the previous and
not repeated here.
As shown in FIG. 12, the combined current collector has two
opposite surfaces. When the cathode 42 is located between two
anodes 44, both surfaces of the combined current collector are
facing to the anode, thus the cathode plate 23 is coupled to both
surfaces of the combined current collector; as for the cathode 42
located outermost, at least one surface of the combined current
collector that is facing to the anode are formed with the cathode
plate 23. The other surface is not particularly limited.
As shown in FIG. 12, the battery 600 comprising two pairs of
cathode 42 and anode 44 has three battery units (not shown)
connected in parallel. In the actual production, the battery
structure can be easily altered by altering the number of cathode
and anode according to usage requirements. As shown in FIG. 13.
although the total battery output voltage has not changed, but the
battery has a higher capacity. The battery structure is flexible,
versatile and has the probability of industrialization.
In a battery system containing neutral electrolyte, it is difficult
to find a cathode current collector which could meets the
requirements of mechanical properties, excellent electrical
properties and stable in the neutral electrolyte. So the
commercialization of aqueous battery has been stalled. The battery
provided in the present invention provides a solution to this
problem. The cathode comprises a cathode current collector, a
conductive film and a cathode plate. The conductive film is formed
on the cathode current collector, which improves the conductivity
of the cathode current collector, and more important protect the
cathode current collector from being corroded by neutral
electrolyte. The cathode current collector can collect and export
electronic stably during discharge process, so as to ensure that
the battery has a stable cycle performance. The battery has good
commercial prospect.
The present invention also provides a battery pack. The battery
pack comprises a number of batteries as described above.
Specifically speaking, more than two batteries are connected in
series or in parallel or combination thereof to produce the battery
pack. Capacity and voltage of the battery pack can be freely
adjusted by changing the connecting mode of batteries. The battery
or battery pack prepared by the batteries can be used as vehicle or
train's power and uninterruptible power supply.
Electrode Plate
The present invention also provides an electrode plate which is
easy processing and sorting and has a uniform thickness and
performance consistency. The battery using this electrode plate has
a low price, good cycle performance and high energy.
As shown in FIG. 14, an electrode plate 1 comprises an
electrochemically inert carrier 2 and an active material layer 4
formed on the carrier 2. The electrode plate 1 can be applied to
cathode or anode of battery. In order to make the battery have a
higher energy density, the preferred thickness range of the
electrode plate 1 is 0.3-1.5 mm. In one embodiment the thickness of
the electrode plate 1 is 0.4 mm.
The active material layer 4 is formed on the carrier 2. The carrier
2 has two opposite surfaces defined as a first surface and a second
surface. Without limited, the active material layer 4 is formed on
both surfaces of the carrier 2 or the active material layer 4 is
formed on the first surface or the second surface.
In the present invention, it should be understood that the
electrode plate 1 comprises the essential active material layer,
but not a current collector. In prior art the usual method to
prepare electrode is to coat slurry with active material on a
current collector. In this process the whole electrode can only be
weighed when sorting cathode. Concerning uneven distribution of
weight of cathode current collector, the weight of cathode active
material cannot be accurately measured, thus cathode capacity will
be different and the battery consistency and qualification rate
will be affected. The electrode plate 1 provided in the present
invention is prepared separately from the current collector. In the
process of preparing the electrode plate 1, the active material
layer 4 could be individually weighed and sorted, which greatly
improve the consistency of the battery and make the battery
assemble easily.
The active material layer 4 comprises an electrode active material,
a binder and a conductive agent. The electrode active material
involves in the electrochemical reaction. The electrode plate 1 can
be applied to different types of batteries, such as nickel-hydrogen
batteries, lead-acid batteries and lithium-ion batteries, based on
the different types of electrode active materials.
In one embodiment, the electrode plate 1 is uses as a cathode; the
electrode active material is a cathode active material. The cathode
active material participates in electrochemical reaction. The
weight percentage of the cathode active material in the cathode
plate is 60-99%. In order to make the cathode have a high capacity,
the surface density range of the cathode active material in the
cathode plate is 200-2000 g/m.sup.2. The cathode active material is
capable of reversibly intercalating and deintercalating a first
metal ion. Preferably the cathode active material is capable of
reversibly intercalating and deintercalating lithium ions, sodium
ions or magnesium ions. The cathode active material has been
described previously and no more repeated here.
The role of the carrier 2 which is electrochemically inert is to
bear the active material layer 4. As known to person in art, the
electrochemically inert carrier does not participate in any
electrochemical reaction which is only in the presence of the
cathode plate to bear the cathode active material. In one
embodiment, the carrier 2 has a porous structure and is electrical
insulation. The pore size range of the carrier 2 is 50 meshes to
200 meshes, which ensure that the carrier 2 has a certain
mechanical properties, and the active material layer 4 could adhere
to the carrier 2 and peeling resistance force of the active
material layer 4 and the carrier 2 is improved. Thus the electrode
plate 1 could stably works in the battery and it is easy for ions
transporting in the electrode active material.
Thickness of the carrier 2 is not particularly limited, and in
order to ensure that the electrode plate 1 has high energy density,
the thickness of the cathode plate should be controlled.
Particularly the thickness range of the carrier 2 is less than 1
mm.
The carrier 2 may be a non-woven fabric. The non-woven fabric is
processed by physical adhesive method without textile processing.
The composition of the non-woven fabric is not particularly limited
except for electrochemically inert. Non-woven fabric is low weight,
stable performance, easy finalizing design and low cost. In the
present invention, the application of non-woven fabric in
combination with the active material layer in the electrode plate
could enable that the electrode plate 1 has a lower weight and more
stable electrochemical performance.
The material of the carrier 2 may be selected from at least one of
polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
polyethylene (PE), polypropylene (PP), polyamide (PA), polyurethane
(PU) and polyacrylonitrile (PAN). These materials can be stably
present in the electrode plate 1 without participating in the
electrochemical reaction, thus the battery has a high energy
density output and low weight.
In prior art the usual method to prepare electrode is to coat
slurry with active material on a current collector. For example, in
lithium ion battery the slurry containing graphite is coated on a
copper foil to form an anode; in lead-acid batteries the lead paste
is coated on grid to form an anode. In this process the whole
electrode can only be weighed when sorting cathode. Concerning
uneven distribution of weight of cathode current collector, the
weight of cathode active material cannot be accurately measured,
thus cathode capacity will be different and the battery consistency
and qualification rate will be affected. In the present invention,
the ratio of the electrode active material, a binder and a
conductive agent in the electrode plate 1 is accurate and
consistent, and the electrochemically inert carrier 2 is a material
with high consistency, thus the weight consistency of the electrode
plate 1 is very high.
Preparation Method of Electrode Plate
The present invention also provides a preparation method of
electrode plate 1 comprising the following steps:
A slurry is prepared and formed on an electrochemically inert
carrier 2 to form an active material layer 4, finally dried
molding; the carrier 2 has a porous structure and is electrical
insulation.
Specifically the slurry comprises an electrode active material
which involves in the electrochemical reaction, a binder and a
conductive agent. The weight percentage range of electrode active
material in the active material layer is 60-99% and the surface
density range of the electrode active material in the active
material layer is 100-3000 g/m.sup.2. In order to make the battery
have a high energy output, preferably the surface density range of
the electrode active material is 200-2000 g/m.sup.2.
The slurry is prepared by dispersing an electrode active material,
a binder and a conductive agent in a dispersant and uniformly
mixing. The dispersant includes but is not limited to water.
After the slurry is mixed, the slurry is formed on the carrier 2.
The method of forming the slurry on the carries is not particularly
limited, including blade coating, screen printing or slurry
pulling.
In one embodiment, the slurry is coated on the carried by a slurry
machine. In general, the slurry machine has a slurry storage tank;
the carrier is guided into the storage tank by rollers and dipped
into the slurry of which the viscosity is 3000-100000mPas. The
carrier 2 is pulled from the storage tank and the slurry is adhered
thereon. The thickness of the slurry can be controlled by blade
which can scrape off the excess slurry and make the slurry more
uniform.
The carrier 2 coated with the slurry is dried. Usually the solvent
in the slurry is removed by evaporation under atmospheric or low
pressure and ambient or elevated temperature. The removal speed of
solvent is maintained basically unchanged along the surface of the
slurry. Preferably the condition of drying is under atmospheric
pressure and 50-130.degree. C., so obtained electrode plate a has a
more uniform thickness. Finally, the electrode plate 1 is cut to a
desired size.
In one embodiment, a slurry is prepared by mixing the cathode
active material LiMn.sub.2O.sub.4, conductive agent Super-P, CMC
and SBR as binder in water, and then the slurry is coated on a
nylon net, dried at 70.degree. C. to obtain a cathode plate which
is rolled to a predetermined thickness.
The method of preparing the electrode plate 1 comprises the steps
of taking a carrier characterized in uniform weight and an
electrochemical inert as a substrate, coating a slurry containing
the electrode active material, binder and conductive agent on the
carrier and obtaining the electrode plate 1 without current
collector. The method is simple. In the process of preparing the
electrode plate, the active material layer can be weighed and
sorted individually. The prepared electrode plate 1 has a uniform
thickness, stable performance. Thus electrode containing the
electrode plate 1 has a good consistency and is easy to
assemble.
Electrode
As shown in FIG. 15, the present invention provides an electrode 6
comprising an electrode current collector 8 and an electrode plate
1. The electrode plate 1 comprises an electrochemically inert
carrier 2 and an active material layer 4 formed on the carrier 2.
The carrier 2 is electrical insulating and has porous
structure.
As shown in FIG. 16, a conductive film 12 is formed on the surface
of the electrode current collector 8 in a certain manner. And then
the electrode plate 1 is coupled to the conductive film 12 form an
electrode 10. Specific to FIG. 16, the conductive film 12 is formed
on both surfaces of the electrode current collector 8. On the one
hand, the conductive film could protect the cathode current
collector from being corroded by the electrolyte. On the other
hand, it helps to reduce the contact resistance between the cathode
current collector and the cathode plate and improve the battery
energy.
Method of Preparing the Electrode
The present invention also provides a method of preparing the
electrode 10 which comprises the following steps.
An electrode plate 1, a conductive film 12 and the electrode
current collector 8 are bonded; the conductive film 12 is located
between the electrode plate 1 and the electrode collector electrode
8. The electrode comprises an electrochemically inert carrier 2 and
an active material layer 4 formed on the carrier 2. The carrier 2
is electrical insulating and has porous structure; the conductive
film 12 comprises a polymer.
In the obtained electrodes 10, the conductive film 12 is located
between the electrode plate 1 and the electrode current collector
8. The electrode collector 8 has two opposite surfaces. Without
particularly limited, the conductive film 12 is formed on either
surfaces or both surfaces of the electrode current collector 8 by
hot pressing. Preferably both surfaces of the electrode current
collector 8 are coated with the conductive film 12 and the
electrode plate 1 one by one by hot pressing.
The electrode 10 may be cathode, anode or bipolar electrode. The
electrode 10 could be applied to different types of batteries, such
as nickel-hydrogen batteries, lead-acid batteries and lithium-ion
batteries by applying different types of the active material layer
of the electrodes 10.
In the electrode plate 1, the active material layer 4 is formed on
the carrier 2 which has two opposite surfaces. Without particularly
limited, the active material layer 4 is formed on either surfaces
or both surfaces of the carrier 2. In addition, the carrier 2 is
electrical insulation and has a porous structure, which ensures
that the carrier has a certain mechanical properties, the active
material layer 4 could adhere to the carrier 2 and peeling
resistance force of the active material layer 4 and the carrier 2
is improved. Thus the electrode plate 1 could stably works in the
battery and it is easy for ions transporting in the electrode
active material.
The active material layer 4 and the carrier 2 have already been
described in detail in the previous and no more repeated here. The
conductive film 12 and the electrode current collector 8 will be
further introduced respectively.
A conductive film 12 is configured between the electrode plate 1
and the electrode current collector 8. The conductive film should
comply with the following requirements: stable and insoluble in the
electrolyte, no swelling, no oxidization in high voltage, easy to
process into a dense, impermeable and electrically conductive film.
On one hand, the conductive film 12 could protect the electrode
current collector from being corroded by the electrolyte. On the
other hand, it helps to reduce the contact resistance between the
electrode current collector 8 and the electrode plate 1 and improve
the battery energy.
In order to enable most effective use of the conductive film 12,
the thickness of the conductive film 12 need to be controlled. The
conductive film 12 with thin thickness is easily damaged and
penetrated by the electrolyte and with bad uniformity; the
conductive film 12 with thick thickness may affect its
conductivity. Preferably the thickness of the conductive film is 10
.mu.m.about.2 mm, thus the conductive film 12 is able to
effectively protect the electrode current collector 8, reduce the
contact resistance between the electrode plate 1 the electrode
current collector 8 and improve the battery energy.
In prior art the usual way to prepare an electrode comprises the
following steps: coating a slurry containing an electrode active
material on a current collector in a certain way. The preparing
method of the electrode 10 in the present invention comprises
combining the electrode plate 1, the conductive film 12 and the
electrode current collector 8 together by hot pressing, thus the
preparation of the electrode can be simplified and production
efficiency can be improved. The conductive film 12 formed between
the electrode plate 1 and the electrode current collector 8 could
reduce the contact internal resistance between the electrode plate
1 and the electrode current collector 8. The electrode 10 has a
good consistency.
The electrode current collector 8 has two opposite surfaces.
Preferably both surfaces of the electrode current collector 8 are
coated with the conductive film 12 and the electrode plate 1 in
turn.
The material of the conductive film 12 has been introduced in the
previous, no more repeated here.
The electrode current collector 8 serves as a carrier of electronic
conduction and collection. The electrode current collector 8 should
meet the requirements of large surface area, good mechanical
properties and good conductivity. The electrode current collector 8
is selected from one of carbon based material, metal or alloy.
The carbon based material is selected from one of glassy carbon,
graphite foil, graphite plate, carbon foam, carbon felt, carbon
cloth and carbon fibre. In one embodiment, the electrode current
collector is graphite, such as commercial graphite pressed foil,
wherein graphite weight rate is in the range 90-100%.
The metal is a metal net or foil which is selected from one of Al,
Fe, Cu, Pb, Ti, Cr, Mo, Co, Ag and passivated metal thereof.
The main purpose of passivating the metal is to form a passivated
oxide film thereon, so that the electrode current collector does
not participate in electrochemical reaction during the process of
battery charging and discharging, which ensures the stability of
battery in the present invention.
The alloy is selected from one of stainless steel, Al alloy, Ni
alloy, Ti alloy, Cu alloy, Co alloy, Ti--Pt alloy, Pt--Rh alloy, or
passivated alloy thereof.
Stainless steel includes stainless steel foil or stainless steel
net. Specifically, the mode of stainless steel can be but not
limited to 300 series stainless steel, such as stainless steel 304,
316 or 316L.
Similarly the main purpose of passivating stainless steel is to
make it stably collect and conduct electron and not participating
in electrochemical reaction. In one embodiment, the process of
passivating stainless steel includes the following steps: preparing
20% HNO.sub.3 solution, controlling the temperature at 50.degree.
C., putting stainless steel mesh or foil in and maintaining for
half an hour, then taking out the stainless steel, washing with
water and drying. The stainless steel being passivated could be
used as an electrode current collector.
Thickness of the electrode current collector 8 has a certain effect
on electrochemical properties of the electrode 10. Thin thickness
will affect the mechanical strength of the electrode current
collector 8; thick thickness will increase the weight of the
electrode 10 and affect the energy density of the electrode 10. In
the present invention the thickness of the electrode current
collector 8 is preferably 10 .mu.m-100 .mu.m to make the battery
have a high energy density output.
For example, the electrode current collector 8 is stainless steel
which could be treated by punching with the preferred pore size
range 500 .mu.m-5 mm; or by polishing with sandpaper to make the
surface of stainless steel rough; or micro corroding with
appropriate weak acid to increase the surface area of stainless
steel without damaging its mechanical properties. The electrode
collector 8 being treated has a large specific surface area, which
helps to improve the compound degree of electrode current collector
8 and the conductive film 12, lower the contact resistance between
the electrode plate 1 and the electrode current collector 8.
Specifically speaking, the electrode plate 1, the conductive film
12 and the electrode current collector 8 are bonded by hot
pressing, which is heating the polymer of the conductive film under
temperature above the glass transition temperature of the polymer
to make the polymer soften and adhere to the current collector,
mean while a certain pressure may be applied. The pressure is not
particularly limited, the main purpose of applying pressure is to
make the electrode plate 1, and the conductive film 12 and
electrode current collector 8 are tightly. Specifically, the
temperature of hot pressing should meet the following criteria:
T.sub.g<T<T.sub.m, wherein T.sub.g is the glass transition
temperature of the polymer of the conductive film, T.sub.m is the
melting point of the polymer of the conductive film.
The electrode could be prepared by one step hot pressing.
Specifically, the conductive film 12 is placed between the
electrode plate 1 and the electrode current collector 8, and then
the electrode plate 1, the conductive film 12 and the electrode
current collector are combined together by hot pressing.
The electrode could be prepared by two steps hot pressing. The
first step of hot pressing is to combining the conductive film 12
with the electrode current collector 8 or combining the conductive
film 12 with the electrode plate 1. Correspondingly, the second
step of hot pressing is to combining the conductive film 12 with
the electrode plate 1, or combining the conductive film 12 with the
electrode current collector 8.
Preferably the first step is to combining conductive film 12 with
the electrode current collector 8. And more preferably two sheets
of the conductive film 12 are bonded to the two opposite surfaces
of the electrode current collector 8.
The electrode current collector 8 is placed between two sheets of
conductive film 12. The area of the conductive film 12 at least
equal to the area of the electrode current collector 8, so that, in
the first step hot pressing, the polymer as the main component of
the conductive film 12 has a certain ductility, the rolled
conductive film 12 completely covers the first surface and the
second surface of the electrode current collector 8, and then the
conductive film 12, electrode current collector 8 and the
conductive film 12 are hot pressed together.
The priority is to combine the conductive film 12 to the electrode
current collector 8. After being rolled the exceeding parts of the
conductive film 12 beyond the electrode current collector 8 could
be completely sealed, which could protect the electrode current
collector 8 from being corroded by the electrolyte. More
importantly, the conductive film 12 can reduce the contact
resistance between the electrode plate 1 and the electrode current
collector 8.
In the second step of hot pressing, two sizable sheets of the
electrode plates are hot pressed onto the conductive film 12 to
obtain the electrode.
The active material layer of the electrode plate further comprises
a polymer binder, of which the weight percent in active material
layer is 0.5 to 10%. Because the amount of polymer binder is less,
there will be no obvious change in polymer binder during hot
pressing process and the shape and performance of the electrode
plate is not affected. Preferably, the temperature of hot pressing
is below the decomposition temperature of the polymer binder.
The conductive film is configured between the electrode plate and
the electrode current collector, which can not only improve the
peeling resistance of the electrode plate and the electrode current
collector and the stability of the electrode, and also reduce
resistance between the electrode plate and the electrode current
collector. A battery containing such an electrode has a high energy
output.
Electrode provided in the present invention can optionally be
configured to form a cathode comprising a cathode plate, a
conductive film and a cathode current collector by hot pressing, to
form an anode comprising an anode plate, a conductive film and an
anode current collector or to form a bipolar electrode comprising a
cathode plate, a conductive film, current collector and an anode
plate.
The present invention will be further illustrated and explained
through the following examples.
Example a1
Zinc methanesulfonate and lithium methanesulfonate are weighed and
dissolved in deionized water. And then an electrolyte containing 2
mol/L zinc methanesulfonate and 2 mol/L lithium methanesulfonate is
obtained and referred to as A1.
Example a2
Zinc methanesulfonate and lithium methanesulfonate are weighed and
dissolved in deionized water. And then an electrolyte containing 2
mol/L zinc methanesulfonate and 5 mol/L lithium methanesulfonate is
obtained and referred to as A2.
Example a3
Zinc methanesulfonate and lithium methanesulfonate are weighed and
dissolved in deionized water; meanwhile a bismuth trioxide is added
therein. And then an electrolyte containing 3 mol/L zinc
methanesulfonate, 3 mol/L lithium methanesulfonate and 1 wt %
bismuth trioxide is obtained and referred to as A3.
Example a4
Zinc methanesulfonate, lithium methanesulfonate, zinc sulfate and
lithium sulfate are weighed and dissolved in deionized water. And
then an electrolyte containing 1 mol/L zinc methanesulfonate, 1
mol/L lithium methanesulfonate, 1 mol/L zinc sulfate and 0.5 mol/L
lithium sulfate is obtained and referred to as A4.
Example a5
Zinc sulfate and lithium sulfate are weighed and dissolved in
deionized water. And then a solution containing 2 mol/L zinc
sulfate and 1 mol/L lithium sulfate is obtained and referred to as
S1.
Zinc methanesulfonate and lithium methanesulfonate, are weighed and
dissolved in deionized water. And then a solution containing 2
mol/L zinc methanesulfonate and 3 mol/L lithium methanesulfonate is
obtained and referred to as S2.
Solution S1 and S2 are mixed in a volume ratio of 10:90 to obtain
an electrolyte which is referred to as A5.
Example a6
In example a6, solution S1 and S2 are mixed in a volume ratio of
25:75 to obtain an electrolyte which is referred to as A6. Solution
S1 and S2 are the same as Example a5.
Example a7
In example a7, solution S1 and S2 are mixed in a volume ratio of
50:50 to obtain an electrolyte which is referred to as A7. Solution
S1 and S2 are the same as Example a5.
Example a8
In example a8, solution S1 and S2 are mixed in a volume ratio of
90:10 to obtain an electrolyte which is referred to as A8. Solution
S1 and S2 are the same as Example a5.
Comparative Example ac1
Zinc sulfate and lithium sulfate are weighed and dissolved in
deionized water. And then an electrolyte containing 2 mol/L zinc
sulfate and 1 mol/L lithium sulfate is obtained and referred to as
AC1.
Battery Preparation
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% conductive
agent graphite, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form a active material layer, and then pressed and cut
to a size 8 cm.times.10 cm (for gas production test) or 6
cm.times.6 cm (for other battery performance test) cathode. The
thickness of the cathode is 0.4 mm and the surface density of the
cathode active material is 750 g/m.sup.2. The combined current
collector comprises 50 .mu.m thick stainless steel mesh which
serves as a cathode current collector and a conductive film coated
thereon.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
The cathode, anode, separator with electrolyte A1-A8 and AC1
respectively are assembled into batteries which are referred to as
B1-B8 and BC1.
Performance Testing
Deep Freezing Test
The electrolyte A1-A4 and AC1 are placed at -20.quadrature. for 12
h, and then taken out to observe whether the electrolytes are
frozen. The test results are shown in Table 1.
TABLE-US-00002 TABLE 1 electrolyte freezing test results
Electrolyte A1 A2 A3 A4 AC1 Whether frozen No frozen No frozen No
frozen No frozen frozen
As can be seen from Table 1, the electrolytes provided by Example
a1-a4 are not frozen, while the electrolyte in comparative example
ac1 after 12 h is frozen, which indicates that the electrolyte
containing alkyl sulfonate ion may inhibit low temperature
freezing, improve the low temperature performance of the
electrolyte, and enhance low temperature durability of the
battery.
Gas Production Testing
Battery B1 and BC1 are placed at 60.degree. C. for one day. The gas
produced by the batteries is collected respectively. The result is
shown in FIG. 17, in which dots represent the result of battery BC1
and squares represent the result of battery B1.
As can be seen from FIG. 17, the amount of gas generated by the
battery BC1 is far more than (almost twice) the amount of gas
generated by the battery B1 per day, which indicates that comparing
to the electrolyte containing sulfate, the electrolyte containing
alkyl sulfonate ion can effectively suppress gas production.
5 g zinc powder is weighed and added to 20 ml electrolyte A1 and
A3, placed at 50.quadrature. for several days, then gas production
is measure respectively. The results are shown in Table 2.
TABLE-US-00003 TABLE 2 gas production of electrolyte A1 and A3
Electrolyte Day 1.sup.st Day 2.sup.nd Day 3.sup.rd Day 4.sup.th Day
5.sup.th A1 29 ml 42 ml 38 ml 23 ml 35 ml A3 22 ml 27 ml 15 ml 11
ml 10 ml
As can be seen from Table 2, the gas production amount of
electrolyte A3 is far less than the gas production amount of
electrolyte A1, which indicates that the combined effect of bismuth
compound and alkyl sulfonate ion in the electrolyte could further
reduce the gas production amount of the battery.
Self-discharge Performance Testing
Cathodes described above are prepared and placed in the electrolyte
A1 and AC1 at 60.quadrature. for one day. Self-discharge rate of
cathode are tested. The results are shown in Table 3.
TABLE-US-00004 TABLE 3 cathode capacity retention in electrolyte A1
and AC1 Electrolyte Capacity Retention/% A1 96.5 AC1 90.4
As can be seen from Table 3, the capacity retention of cathode in
the electrolyte A1 is much larger than the capacity retention of
cathode in the electrolyte in AC1.
The battery B5-B8 and BC1 are stored at 60.quadrature. for 24 hours
and then withstood a cycle of discharge and charge. The
aforementioned steps are repeated nine times. The remaining
capacity of the batteries are tested and shown in Table 4.
TABLE-US-00005 TABLE 4 self-discharge of battery B5-B8 at
60.degree. C. Battery Capacity Retention B5 94.3% B6 96.1% B7 94.0%
B8 90.0% BC1 87.0%
As can be seen from Table 4, the capacity retention of battery
B5-B8 has improved dramatically comparing to battery BC1, which
shows that the addition of alkyl sulfonate in electrolyte can
effectively suppress the self-discharge of battery.
Rate Discharge Performance Testing
Battery B1 and BC1 are charged and discharged with a 0.2 C rate, 1
C rate and 3 C rate for three times each, then cycled with a 1 C
rate.
Taking discharge capacity with a 0.2 C rate as a baseline, the
discharge capacity of battery B1 with a 3 C rate is 52.8%, with a 1
C rate is 95%. The discharge capacity of battery BC1 with 3 C rate
and 1 C rate are 35% and 60% respectively. This shows that the
electrolyte can effectively improve the high-rate cycling
performance of battery.
Example c1
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 8 cm.times.10 cm cathode. The thickness of the
cathode is 0.4 mm and the surface density of the cathode active
material is 750 g/m.sup.2. The combined current collector comprises
50 .mu.m thick stainless steel mesh which serves as a cathode
current collector and a conductive film coated thereon.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water; meanwhile a bismuth trioxide is added therein. And then an
electrolyte containing 2 mol/L zinc sulfate, 1 mol/L lithium
sulfate and 1 wt % bismuth trioxide is obtained.
The electrolyte is added dropwise to one side of the separator, and
then the cathode, the separator and the anode are stacked and
loaded into a case, then a battery is formed and referred to as C1.
The side with the electrolyte faces to the anode.
Example c2
In Example c2, the content of the bismuth trioxide is 2 wt %. The
other part of the battery is the same as example c1. The battery is
referred to as C2.
Example c3
In Example c3, the content of the bismuth trioxide is 0.1 wt %. The
other part of the battery is the same as example c1. The battery is
referred to as C3.
Example c4
In Example c4, the content of the bismuth trioxide is 10 wt %. The
other part of the battery is the same as example c1. The battery is
referred to as C4.
Example c5
In Example c5, the bismuth trioxide is replaced by bismuth nitrate.
The other part of the battery is the same as example c1. The
battery is referred to as C5.
Example c6
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5 wt % graphite
as conductive agent, 2.5 wt % SBR and 2.5 wt % CMC as binder in
water. The cathode slurry is coated evenly on both sides of a
combined current collector to form an active material layer, and
then pressed and cut to a size 6 cm.times.6 cm cathode. The
thickness of the cathode is 0.4 mm and the surface density of the
cathode active material is 750 g/m.sup.2. The combined current
collector comprises 50 .mu.m thick stainless steel mesh which
serves as a cathode current collector and a conductive film coated
thereon.
An anode slurry is prepared by dissolving 90 wt % zinc powder as
the anode active material, 1 wt % bismuth trioxide and 9 wt % PTFE
as binder in water. The slurry is coated on a stainless steel
plate, and then pressed into the anode.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water. And then an electrolyte containing 2 mol/L zinc sulfate and
1 mol/L lithium sulfate is obtained.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is added with the electrolyte, and then
sealed. A battery is formed and referred to as C6.
Example c7
In Example c7, the bismuth trioxide is replaced by bismuth nitrate.
The other part of the battery is the same as example c6. The
battery is referred to as C7.
Example c8
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 6 cm.times.6 cm cathode. The thickness of the cathode
is 0.4 mm and the surface density of the cathode active material is
750 g/m.sup.2. The combined current collector comprises 50 .mu.m
thick stainless steel mesh which serves as a cathode current
collector and a conductive film coated thereon.
An anode slurry is prepared by dissolving 90 wt % zinc powder as
the anode active material, 1 wt % bismuth trioxide and 9 wt % PTFE
as binder in water. The slurry is coated on a stainless steel
plate, and then pressed into the anode.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water; meanwhile a bismuth trioxide is added therein. And then an
electrolyte containing 2 mol/L zinc sulfate, 1 mol/L lithium
sulfate and 0.01 wt % bismuth trioxide is obtained.
The electrolyte is added dropwise to one side of the separator, and
then the cathode, the separator and the anode are stacked and
loaded into a case, then a battery is formed and referred to as C8.
The side with the electrolyte faces to the anode.
Comparative Example cc1
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on a 50 .mu.m thick stainless steel
mesh which serves as a cathode current collector to form an active
material layer, and then pressed and cut to a size 6 cm.times.6 cm
cathode. The thickness of the cathode is 0.4 mm and the surface
density of the cathode active material is 750 g/m.sup.2.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water. And then an electrolyte containing 2 mol/L zinc sulfate and
1 mol/L lithium sulfate is obtained.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is added with the electrolyte and sealed. A
battery is formed and referred to as CC1.
Gas Production Testing
Battery C1 and CC1 are charged and discharged at 60.quadrature. for
several cycles, laid up for 20 h, then discharged for 5 h, laid up
for 20 h, and finally charged for 6 h. Gas production amount of
battery is recorded per hour. The results are shown in FIG. 18. In
FIG. 18, 1 represents battery C1 and 2 represents battery CC1.
As can be seen from FIG. 18, no matter in standing or in charging
and discharging, the amount of gas production of battery C1 is far
less than that of battery CC1. This shows that the battery can
effectively suppress the generation of gas.
Battery C1-C4 and CC1 are placed at 50.degree. C. and room
temperature (RT) for several days. The cumulative amount of gas
production of battery is recorded. The results are shown in Table
5.
TABLE-US-00006 TABLE 5 gas production amount at 50.quadrature. and
room temperature content of bismuth 50.quadrature./ml RT/ml Battery
compound Day 1.sup.st Day 2.sup.nd Day 3.sup.rd Day 1.sup.st C3
0.1% 49 110 152 5 C1 1.0% 41 109 143 7 C2 2.0% 45 118 162 9 C4
10.0% 47 126 195 20 CC1 0.0% 85 176 290 21
As can be seen from Table 5, the amount of gas production of
battery C1-C4 is less than that of battery CC1 at room temperature.
Especially the amount of gas production of battery C1-C3 is more
than times less than that of battery CC1. The amount of gas
production of battery C1-C4 is less than that of battery CC1 at
50.quadrature.. This shows that the battery of the present
invention can effectively suppress the generation of gas no matter
in standing at room temperature or high temperature.
Example d1
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 6 cm.times.6 cm cathode. The combined current
collector comprises 50 .mu.m thick stainless steel plate which
serves as a cathode current collector and a conductive film coated
thereon.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water. Meanwhile gelatin is added therein. And then an electrolyte
containing 2 mol/L zinc sulfate, 1 mol/L lithium sulfate and 0.05
wt % gelatin is obtained.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is added with the electrolyte and sealed.
Then a battery is formed and referred to as D1.
Example d2
In example d2, the content of gelatin is 0.01 wt %. The other part
of battery is the same as example d1. The battery is referred to as
D2.
Example d3
In example d3, the content of gelatin is 0.5 wt %. The other part
of battery is the same as example d1. The battery is referred to as
D3.
Example d4
In example d4, the electrolyte is a water solution containing 2
mol/L zinc methanesulfonate, 3 mol/L lithium methanesulfonate and
0.05 wt % gelatin. The battery is referred to as D4.
Example d5
In example d5, the content of gelatin is 0.01 wt %. The other part
of battery is the same as example d4. The battery is referred to as
D5.
Example d6
In example d6, the content of gelatin is 0.5 wt %. The other part
of battery is the same as example d4. The battery is referred to as
D6.
Example d7
In example d7, the gelatin is replaced by dextrin. The other part
of battery is the same as example d1. The battery is referred to as
D7.
Example d8
In example d8, the gelatin is replaced by agar. The other part of
battery is the same as example d1. The battery is referred to as
D8.
Example d9
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 6 cm.times.6 cm cathode. The combined current
collector comprises 50 .mu.m thick stainless steel plate which
serves as a cathode current collector and a conductive film coated
thereon.
Zinc methanesulfonate and lithium methanesulfonate are weighed and
dissolved in water. Meanwhile gelatin is added therein. And then an
electrolyte containing 2 mol/L zinc methanesulfonate and 3 mol/L
lithium methanesulfonate is obtained.
The anode is a 50 .mu.m thick zinc foil. A dispersion is prepared
containing 2 wt % gelatin and 98 wt % zinc sulfate with a
concentration of 1.5 mol/L. the dispersion is coated on the anode,
then dried.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is added with the electrolyte and sealed.
Then a battery is formed and referred to as D9.
Example d10
In example d10, a dispersion is prepared containing 20 wt % gelatin
and 80 wt % zinc sulfate with a concentration of 1.5 mol/L. The
other part of battery is the same as example d9. The obtained
battery is referred to as D10.
Comparative Example dc1
A cathode homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% graphite as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
cathode slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 6 cm.times.6 cm cathode. The combined current
collector comprises 50 .mu.m thick stainless steel plate which
serves as a cathode current collector and a conductive film coated
thereon.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
Zinc sulfate and lithium sulfate are weighed and dissolved in
water. And then an electrolyte containing 2 mol/L zinc sulfate and
1 mol/L lithium sulfate is obtained.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is added with the electrolyte and sealed. A
battery is formed and referred to as DC1.
Comparative Example dc2
In comparative example dc2, the electrolyte is a water solution
containing 2 mol/L zinc methanesulfonate and 3 mol/L lithium
methanesulfonate. The other part of battery is the same as
comparative example dc1. The obtained battery is referred to as
DC2.
Dendrite Testing at Room Temperature
The batteries D1-D10 and DC1-DC2 are charged and discharged at room
temperature for a set time, and then disassembled to observe
dendrite. The results are shown in Table 6.
TABLE-US-00007 TABLE 6 observation results of dendrite Zinc
deposition Dendrite Dendrite Battery Cycles on separator on
separator on anode D1 70 No deposition No No D2 70 No deposition No
No D3 70 No deposition No No D4 70 No deposition No No D5 70 No
deposition No No D6 70 No deposition No No D7 30 No deposition No
No D8 30 No deposition No No D9 45 A little zinc deposition No No
D10 75 A little zinc deposition No No DC1 30 Lots of zinc
deposition Lots of Lots of dendrite dendrite DC2 30 Lots of zinc
deposition Lots of Lots of dendrite dendrite
As can be seen from Table 6, there are no obvious dendrite of
batteries D1-D6 after 70 cycles, batteries D7-D8 after 30 cycles,
battery D9 after 45 cycles and battery D10 after 75 cycles. There
are a lot of dendrite of batteries DC1 and DC2 after 30 cycles.
This indicates that the addition of anode modifier can greatly
suppress dendrite generation of anode, which could effectively
improve the safety performance of the battery.
Dendrite Testing at High Temperature
The batteries D1-D6 are charged and discharged at 60.degree. C. for
10 cycles, and then disassembled to observe dendrite. The results
are shown in Table 7.
TABLE-US-00008 TABLE 7 observation results of dendrite Zinc
deposition Dendrite Dendrite Battery on separator on separator on
anode D1 No deposition No No D2 No deposition No No D3 No
deposition No No D4 No deposition No No D5 No deposition No No D6
No deposition No No
As can be seen from Table 7, there is no dendrite of batteries
D1-D6 at 60.degree. C. This shows that the anode modifier is well
dispersed in the electrolyte. Even at 60.degree. C. it could still
well suppress the generation of anode dendrite and improve the high
temperature performance of the battery.
Gas Production Testing
5 g zinc powder is weighed, added to 20 ml electrolyte D2 and DC2
respectively, and then sealed, laid up at 50.degree. C. for 3 days.
The amounts of gas production per day are recorded. The test
results are shown in Table 8.
TABLE-US-00009 TABLE 8 gas production amount of electrolyte D2 and
DC2 at 50.quadrature. gas production amount/mL Electrolyte Day
1.sup.st Day 2.sup.nd Day 3.sup.rd D2 7.3 8 15.3 DC2 54 50 64
As can be seen from Table 8, the amount of gas production of
battery D2 is much lesser than that of battery DC2. This shows that
the addition of anode modifier in the electrolyte can effectively
suppress the side reaction between the anode active material and
the electrolyte and reduce the gas production.
Example f1
A cathode homogeneous slurry is prepared by dissolving 86.5 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 10% graphite as
conductive agent, 2.5% SBR and 1% CMC as binder in water. The
median size d50 of graphite is 3.4 .mu.m, and the particle size d10
of graphite is 2 .mu.m. The cathode slurry is coated evenly on both
sides of a combined current collector to form an active material
layer, and then pressed and cut to a size 6 cm.times.6 cm cathode.
The combined current collector comprises 100 .mu.m thick stainless
steel plate which serves as a cathode current collector and a
conductive film coated thereon.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
The electrolyte is a water solution containing 2 mol/L zinc sulfate
and 1 mol/L lithium sulfate.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is injected with the electrolyte and sealed.
Then a battery is formed.
Example f2
In example f2, the median size d50 of graphite is 8.0 .mu.m, and
the particle size d10 of graphite is 3 .mu.m. The other part of
battery is the same as example f1.
Example f3
In example f3, the median size d50 of graphite is 18.6 .mu.m, and
the particle size d10 of graphite is 5 .mu.m. The other part of
battery is the same as example f1.
Example f4
In example f4, the median size d50 of graphite is 36.1 .mu.m; the
particle size d10 of graphite is 10 .mu.m. The other part of
battery is the same as example f1.
Comparative Example fc1
A cathode homogeneous slurry is prepared by dissolving 90.5 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 6% carbon black
(Super-P) as conductive agent, 2.5% SBR and 1% CMC as binder in
water. The median size d50 of Super-P is 0.2 .mu.m. The cathode
slurry is coated evenly on both sides of a combined current
collector to form an active material layer, and then pressed and
cut to a size 6 cm.times.6 cm cathode. The combined current
collector comprises 100 .mu.m thick stainless steel plate which
serves as a cathode current collector and a conductive film coated
thereon.
The other part of battery is the same as example f1.
Example f5
In example f5, the electrolyte is a water solution containing 2
mol/L zinc methanesulfonate and 3 mol/L lithium methanesulfonate.
The other part of battery is the same as example f1.
Example f6
In example f6, the electrolyte is a water solution containing 2
mol/L zinc methanesulfonate and 3 mol/L lithium methanesulfonate.
The other part of battery is the same as example f2.
Example f7
In example f7, the electrolyte is a water solution containing 2
mol/L zinc methanesulfonate and 3 mol/L lithium methanesulfonate.
The other part of battery is the same as example f3.
Example f8
In example f8, the electrolyte is a water solution containing 2
mol/L zinc methanesulfonate and 3 mol/L lithium methanesulfonate.
The other part of battery is the same as example f4.
Comparative Example fc2
In comparative example fc2, the electrolyte is a water solution
containing 2 mol/L zinc methanesulfonate and 3 mol/L lithium
methanesulfonate. The other part of battery is the same as example
fc1.
Gas Production Testing
The batteries are fully charged and the cathodes are taken out and
placed in syringes respectively. The syringes are added with
electrolyte and sealed. The amount of gas production per day is
tested. The test results are shown in Table 9 for the gas
production at 60.degree. C.
As can be seen from Table 9, when the electrolyte of the battery is
sulfate, the gas production of cathode containing conductive agent
graphite has been significantly suppressed. The gas production
amount fell from 10 ml to 4-5 ml at the first day; the accumulative
gas production amount of six days fell from 25 ml to 5-7 ml. This
result indicates that the conductive agent of cathode provides a
good stability and corrosion resistance.
Additionally when the electrolyte of the battery is
methanesulfonate, the gas production of cathode containing
conductive agent graphite has been significantly suppressed. The
gas production amount fell from 4.5 ml to 3-4 ml at the first day;
the accumulative gas production amount of six days fell from 7.3 ml
to 4-5 ml. This result further indicates that the conductive agent
has a good stability and corrosion resistance. Meanwhile the
combination of conductive agent graphite and methanesulfonate could
further suppress gas production of cathode, which can be seen from
that the amount of gas production of cathode in comparative example
fc2 is less than that in comparative example fc1.
TABLE-US-00010 TABLE 9 Gas production D50 of amount at 60.degree.
C./ml Cathode graphite/.mu.m Electrolyte Day 1.sup.st Day 6.sup.th
Example f1 3.4 Sulfate 5 7 Example f2 8.0 4 6 Example f3 18.6 4 5
Example f4 36.1 4 5 Comparative 0.2 10 25 example fc1 Example f5
3.4 Methanesulfonate 4 6 Example f6 8.0 4 5 Example f7 18.6 3 4
Example f8 36.1 3 4 Comparative 0.2 4.5 7.3 example fc2
Self-discharge Testing
The batteries provided in Example f1-f8 and comparative fc1-fc2 are
fully charged, laid up at 60.degree. C. for one day or at room
temperature (RT) for 28 days. The remaining battery capacity is
tested. The test results are shown in Table 10. Table 10 shows the
capacity retention of battery after laying up at 60.degree. C. for
one day or at room temperature for 28 days.
TABLE-US-00011 TABLE 10 Capacity Retention/% Battery Electrolyte
60.degree. C. RT Example f1 Sulfate 89 85 Example f2 91 87 Example
f3 93 89 Example f4 93 89 Comparative 68 77 example fc1 Example f5
Methanesulfonate 94 89 Example f6 97 91 Example f7 96 92 Example f8
96 92 Comparative 91 84 example fc2
As can be seen from table 10, batteries containing conductive agent
exhibit relatively high capacity retention, while, the battery
containing methanesulfonate electrolyte has positive effect on
improving the capacity retention.
Example f9
A cathode homogeneous slurry is prepared by dissolving 86.5 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 10% graphite as
conductive agent, 2.5% SBR and 1% CMC as binder in water. The
median size d50 of graphite is 8.0 .mu.m, and the particle size d10
of graphite is 3 .mu.m. The cathode slurry is coated evenly on both
sides of a combined current collector to form an active material
layer, and then pressed and cut to a size 6 cm.times.6 cm cathode.
The combined current collector comprises 100 .mu.m thick stainless
steel plate which serves as a cathode current collector and a
conductive film coated thereon.
The anode active material is a 50 .mu.m thick zinc foil. The anode
current collector is a 20 .mu.m thick brass foil. Zinc foil and
brass foil are stacked to form the anode.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
The electrolyte is a water solution containing 2 mol/L zinc sulfate
and 1 mol/L lithium sulfate.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is injected with the electrolyte and sealed.
Then a battery is formed.
Example f10
In example f10, a cathode homogeneous slurry is prepared by
dissolving 84.5 wt % LiMn.sub.2O.sub.4 as the cathode active
material, 12% graphite as conductive agent, 2.5% SBR and 1% CMC as
binder in water. The other part of cathode and battery are the same
as example f9.
Self-discharge Testing
Batteries provided by example f9 and f10 are charged with constant
current of 0.2 C to 2.1V, then charged with constant voltage until
the current is reduced from 0.2 C to 0.02 C. the batteries are
placed at 60.degree. C. for one day and cooled. The capacity loss
of batteries is tested.
The capacity loss of battery in example f9 is 12% after being
placed at 60.degree. C. for one day and the capacity loss of
battery in example f10 is 13%, the result indicates that the
increasing of graphite content in cathode slurry may slightly
increase self-discharge of battery.
Float Charge Testing
Batteries provided by example f9 and f10 are charged with a 0.2 C
rate to 2.0V at room temperature and batteries capacity are
calibrated. Then the batteries are float charged for 168 hours and
discharged with a 0.2 C rate to 1.4V. The discharge capacities of
batteries are test. The discharge capacity decreasing to 50% of the
calibration capacity is defined as float charge life.
The float charge life of batteries in example f9 and f10 are 2
weeks and 4 weeks respectively, which shows that the increasing of
graphite content in cathode slurry may has slight side effect on
self-discharge of battery, but could doubled float charge life of
battery.
Example r1
A homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% Super-P as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
solid content of water is 60-70%. A nylon net is fully immersed
into the slurry, taken out and dried at 60.degree. C. to form a
cathode plate with an active material layer. Then the cathode plate
is cut to size 6 cm.times.6 cm. The thickness of the cathode plate
is 0.4 mm and the density of the cathode active material is 750
g/m.sup.2.
The conductive film is a composite with polyethylene and conductive
carbon black. The thickness of the conductive film is 50 .mu.m.
The cathode current collector is a 50 .mu.m thick punching carbon
steel.
A combined current collector is formed by hot pressing method.
Specifically the cathode current collector is placed in the middle
of two conductive films. The size of the conductive film is
slightly larger than the cathode current collector. The conductive
film and cathode current collector are combined together at
115-140.degree. C. through air pressure machine with pressure of
0.5 MPa, and the exceeding parts of the conductive film beyond the
punching carbon steel is well sealed.
The combined current collector is placed in the middle of two
cathode plates. Repeat above steps to prepare the cathode. The
pressing time of the air pressure machine is 10 seconds.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
The electrolyte is a water solution containing 2 mol/L zinc sulfate
and 1 mol/L lithium sulfate.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is injected with the electrolyte and sealed.
Then a battery is formed. The battery is stood for 3 hours and then
charged and discharged.
Charge and Discharge Testing
The battery is charged and discharged with a 0.2 C constant
current. The voltage range of charge and discharge is 1.4-2.1V.
Example r2
In example r2, the thickness of the conductive film is 100 .mu.m.
The other part of battery is the same as example r1.
Example rc1
In example rc1, the cathode is prepared not by hot pressed but
physically stacked of cathode plate, conductive film and cathode
current collector. The other part of battery is the same as example
r1.
FIG. 19 is an internal resistance-time curve during charging and
discharging of batteries in example r1 and rc1. In FIG. 1
-.box-solid.- represents charging process of the battery in
comparative example rc1; -.circle-solid.- represents discharging
process of the battery in comparative example rc1;
-.tangle-solidup.- represents charging process of the battery in
example r1; -- represents discharging process of the battery in c
example r1.
As can be seen from FIG. 19, the curve plateau of internal
resistance of battery in example r1 is lower than that of battery
in comparative example rc1. Meanwhile with the increase of charge
and discharge cycles of battery, there is no change of the internal
resistance of battery in example r1, but the internal resistance of
battery in comparative example rc1 is gradually increasing. The
results show that the cathode prepared by hot pressing method has
low internal resistance, which could enables that the battery with
the cathode has an excellent and stable cycle performance. In
addition, the performance of battery in example r2 is better than
that in example r1, which indicates that the conductive film
thickness has a certain influence on the battery performance;
battery with a 100 .mu.m thick conductive film has a better cycle
performance.
Example r3
A homogeneous slurry is prepared by dissolving 90 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 5% Super-P as
conductive agent, 2.5% SBR and 2.5% CMC as binder in water. The
solid content of water is 60-70%. A nylon net is fully immersed
into the slurry, taken out and dried at 60.degree. C. to form a
cathode plate with an active material layer. Then the cathode plate
is cut to size 8 cm.times.10 cm. The thickness of the cathode plate
is 0.4 mm and the density of the cathode active material is 750
g/m.sup.2.
The cathode current collector is a 50 .mu.m thick punching carbon
steel. The cathode plate and the cathode current collector with the
same size are stacked to form the cathode. The method of preparing
the cathode is defined as separate manufacturing method.
The anode is a 50 .mu.m thick zinc foil. An AGM glass fiber is used
as separator. The size of the anode and separator is the same as
the cathode.
The electrolyte is a water solution containing 2 mol/L zinc sulfate
and 1 mol/L lithium sulfate. The pH of the electrolyte is adjusted
to 4.
Five cathodes and six anodes are staggered and loaded into a case.
Cathode and anode is separated with the separator. The case is
injected with 170 ml electrolyte and sealed. Then a battery is
formed. The battery is stood for 3 hours and then charged and
discharged with a 0.2 C rate. The voltage range is 1.4-2.1V.
Example rc2
In example rc2, the cathode is prepared by directly coating the
slurry on the cathode current collector, drying and cutting to a
desired size. The other part of battery is the same as example r3.
The method of preparing the cathode is defined as slurry
method.
FIG. 20 is a voltage-discharge capacity curve of batteries in
example r3 and comparative example rc2. As can be seen from FIG.
20, the discharge capacity of battery in example r3 is higher than
that of battery in Comparative example rc2. The results show that
the battery containing a cathode plate which is separately prepared
has a higher discharge capacity comparing to the battery containing
a cathode which is prepared by coating the cathode active material
directly on the cathode current collector.
Table 11 shows the capacity of five batches cathode plates
respectively prepared by the methods provided by example r3 and
rc2. As can be seen from table 11, the capacity tolerance
(difference between the maximum capacity and the minimum capacity)
of cathode plates prepared by the methods provided by example r3 is
smaller and the cathode plates has an excellent capacity
consistency, which indicates that the cathode plate has a very
significant effect on improving battery consistency.
TABLE-US-00012 TABLE 11 Cathode plate batch Capacity/mAh
(Theoretical capacity separate Capacity/mAh 1200 mAh) manufacturing
method Slurry Method 1 1211 1253 2 1205 1239 3 1203 1104 4 1194
1191 5 1199 1189 Capacity Tolerance .+-.17 mAh .+-.149 mAh
Example r4
A homogeneous slurry is prepared by dissolving 86.5 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 10% graphite as
conductive agent, 2.5% SBR and 1% CMC as binder in water. A nylon
net is fully immersed into the slurry, taken out the nylon net
containing the slurry and dried at 60.degree. C. to form a cathode
plate with an active material layer. Then the cathode plate is cut
to size 6 cm.times.6 cm. The thickness of the cathode plate is 0.4
mm and the density of the cathode active material is 750
g/m.sup.2.
The conductive film is a composite with polyethylene and conductive
carbon black. The thickness of the conductive film is 100
.mu.m.
The cathode current collector is a 50 .mu.m thick punching carbon
steel.
A combined current collector is formed by hot pressing method.
Specifically the cathode current collector is placed in the middle
of two conductive films. The size of the conductive film is
slightly larger than the cathode current collector. The conductive
film and cathode current collector are combined together at
115-140.degree. C. through air pressure machine with pressure of
0.5 MPa, and the exceeding parts of the conductive film beyond the
punching carbon steel is well sealed.
The prepared combined current collector and the cathode plate are
folded together. Repeat above steps to prepare the cathode. The
pressing time of the air pressure machine is 10 seconds.
The anode includes an anode current collector and an anode active
material. The anode current collector is a 10 .mu.m thick brass
foil and the anode active material is a 50 .mu.m thick zinc
foil.
The electrolyte is a water solution containing 2 mol/L zinc
methanesulfonate and 3 mol/L lithium methanesulfonate. The pH of
the electrolyte is adjusted to 3.5.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
The cathode, the separator and the anode are stacked and loaded
into a case. The case is injected with the electrolyte and sealed.
Then a battery is formed. The battery is stood for a while and then
charged and discharged.
Charge and Discharge Testing
The battery is charged and discharged with a 0.2 C rate. The charge
and discharge voltage range is 1.4-2.1V.
FIG. 21 is a cycles-discharge capacity curve of batteries in
example r4. As can be seen from FIG. 21, the battery has stable
cycle performance.
Example r5
A homogeneous slurry is prepared by dissolving 86.5 wt %
LiMn.sub.2O.sub.4 as the cathode active material, 10% graphite as
conductive agent, 2.5% SBR and 1% CMC as binder in water. A nylon
net is fully immersed into the slurry, taken out the nylon net
containing the slurry and dried at 60.degree. C. to form a cathode
plate with an active material layer. Then the cathode plate is cut
to size 8 cm.times.10 cm. The thickness of the cathode plate is 0.4
mm and the density of the cathode active material is 750
g/m.sup.2.
The conductive film is a composite with polyethylene and conductive
carbon black. The thickness of the conductive film is 100
.mu.m.
The cathode current collector is a 50 .mu.m thick punching carbon
steel.
A combined current collector is formed by hot pressing method.
Specifically the cathode current collector is placed in the middle
of two conductive films. The size of the conductive film is
slightly larger than the cathode current collector. The conductive
film and cathode current collector are combined together at
115-140.degree. C. through air pressure machine with pressure of
0.5 MPa, and the exceeding parts of the conductive film beyond the
punching carbon steel is well sealed.
The prepared combined current collector is placed in the middle of
two cathode plates and stacked together.
The anode includes an anode current collector and an anode active
material. The anode current collector is a 10 .mu.m thick brass
foil and the anode active material is a 50 .mu.m thick zinc foil.
Zinc foil is placed in the middle of two brass foil and stacked
together.
An AGM glass fiber is used as separator. The size of the anode and
separator is the same as the cathode.
The electrolyte is a water solution containing 2 mol/L zinc sulfate
and 1 mol/L lithium sulfate. The pH of the electrolyte is adjusted
to 3.5.
Six cathodes and seven anodes are staggered and loaded into a case.
Cathode and anode is separated with the separator. The case is
injected with 170 ml electrolyte and sealed. Then a battery with a
theoretical capacity 6 Ah is formed. The battery is stood for 3
hours and then tested. The battery is charged with a 0.2 C constant
current and with a 2.05V or 2.1V constant voltage, discharged with
a 0.2 C constant current. The voltage range is 1.4-2.1V.
FIG. 22 is a cycles-discharge capacity curve of batteries in
example r5. As can be seen from FIG. 22, the discharge capacity of
the battery is very stable; the discharge capacity of the battery
is nearly 6 Ah after 40 cycles with no loss, which indicates the
battery has a stable cycle performance.
Aspects of the present invention are described above by means of
various illustrative examples. The examples contained herein are
not intended to limit the invention in any way but to illustrate
same in more detail. It should be understood that the experiments
in the following examples, unless otherwise indicated, are in
accordance with conditions as would be known to persons skilled in
the art or the conditions recommended by manufacturers.
* * * * *
References